9-06. CTW TIM Definitions.pdf

general group reference id condition description geofence description timing description suggested display icon ITIS code and phrase sequence emergency-warning wrong_way_vehicle_detected

• Wrong way vehicle detection systems have reported a wrong way vehicle at the threshold of entering the roadway going the wrong way.

• This message is an upstream warning.

• Roadway path

• Path ends within 50 feet of where the exit ramp where the wwd has entered the roadway.

• Path starts upstream from the exit ramp location at a distance determined by IOO traffic operations.

• Active period starts as soon as roadside systems alerts to WWD.

• Active period ends within a few minutes of the generated start time -duration depends on upstream distance.

• Maximum duration 5 minutes. 6917 13569 1793 2822 danger ahead vehicle-traveling-wrong-way confirmed-report incident-management incident_ahead

• Event or incident on or near roadway is affecting traffic flow.

• This message is an upstream warning.

• Roadway path

• Path ends within 50 feet of incident location

• Path starts upstream from incident location at a distance determined by IOO traffic operations.

• Active period starts as soon as IOO can confirm an incident.

• Active period ends when IOO confirms that the incident is cleared and normal traffic flow is restored. 531 13569 incident ahead incident-management right_lane_blocked_ahead

• Right/left/center lane is blocked due to an incident or event. Typically there are no temporary traffic control devices set up, there may be a responder that is providing a traffic break.

• This message is an upstream warning.

• This is contrasted with a lane closure.

• Roadway path

• Path ends within 50 feet upstream of lane blockage or point where responders are diverting traffic.

• Path starts upstream from lane blockage at a distance determined by IOO traffic operations.

• Active period starts as soon as IOO can confirm lane blockage associated with an event or incident.

• Active period ends when IOO confirms that the lane blockage is cleared and lane diversion is no longer required. 8196 776 right-lane blocked-ahead incident-management left_lane_blocked_ahead 8195 776 left-lane blocked-ahead incident-management center_lane_blocked_ahead 8197 776 center-lane blocked-ahead incident-management right_n_lanes_blocked_ahead

• Multiple lanes blocked right/left/center.

• Number of blocked lanes must be specified.

• This message is an upstream warning

• Roadway path

• Path ends within 50 feet upstream of lane blockage or point where responders are diverting traffic.

• Path starts upstream from lane blockage at a distance determined by IOO traffic operations. 13579

<small number> e.g. 12546 = 2 13588 776 right <number> lane blocked-ahead incident-management left_n_lanes_blocked_ahead 13580 <small number> e.g. 12546 = 2 13588 776 left <number> lane blocked-ahead incident-management center_n_lanes_blocked_ahead 13635 <small number> e.g. 12546 = 2 13588 776 center <number> lane blocked-ahead incident-management disabled_vehicle_ahead

• disabled vehicle located on either right or left shoulder of the road, not in traffic lanes.

• Vehicle personnel and/or responders are also at the disabled vehicle location.

• This message is an upstream warning.

• Roadway path

• Path ends within 50 feet upstream of the disabled vehicle location.

• Path starts upstream from the disabled vehicle location at a distance determined by IOO traffic operations.

• Active period starts as soon as IOO can confirm disabled vehicle near roadway.

• Active period ends when IOO confirms that the disabled vehicle has been resolved and the vehicle and any responders have left the scene or the vehicle has been moved to a safe roadside location and all personnel have left the secne. 534 13569 disabled-vehicle ahead

CTW Traveler Information Message Summary Table work-zone road_construction

• Identifies the extent of a workzone along a roadway.

• Roadway path

• Start at beginning of defined construction zone

• End at last downstream point of construction zone

• Active period starts when the work zone is first established on the roadway

• Active period ends when the work zone has been cleared from the roadway and normal traffic flow is restored. 1025 road-construction work-zone right_lane_closed_ahead

• Right/left/center lane is closed due to construction or other planned activity.

There are temporary traffic control devices set up to implement the lane closure.

• This message is an upstream warning.

• This is contrasted with an incident related lane blockage.

• Roadway path

• Path ends where traffic control devices begin the lane closure taper.

• Path starts upstream from lane closure at a distance determined by IOO traffic operations.

• Active period starts when the temporary traffic control devices are being set up to implement the lane closure.

• Active period ends when all traffic control devices have been cleared from the roadway and normal traffic flow is restored. 8196 771 right-lane closed-ahead work-zone left_lane_closed_ahead 8195 771 left-lane closed-ahead work-zone center_lane_closed_ahead 8197 771 center-lane closed-ahead work-zone right_n_lanes_closed_ahead

• Multiple lanes closed right/left/center.

• Number of lanes closed must be specified.

• This message is an upstream warning

• Roadway path

• Path ends where traffic control devices begin the lane closure taper for the final lane being closed.

13579 <small number> e.g. 12546 = 2 13588 771 right <number> lane closed-ahead work-zone left_n_lanes_closed_ahead 13580 <small number> e.g. 12546 = 2 13588 771 left <number> lane closed-ahead work-zone center_n_lanes_closed_ahead 13635 <small number> e.g. 12546 = 2 13588 771 center <number> lane closed-ahead work-zone look_out_for_workers

• Identifies area of a work zone that is active and has workers present

• Roadway Path

• Path bounds area where workers are present and begins and ends within 200 feet on either side of this area.

• Message is active only when workers are present 6952 look-out-for-workers work-zone right_shoulder_closed_ahead

• Right/left shoulder is closed due to construction or maintence work.

• This message is an upstream warning.

• Roadway Path

• Path ends at the point where the shoulder closure begins

• Active period starts when the shoulder restriction is first established on the roadway

• Active period ends when the shoulder restriction has been cleared from the roadway. 8208 771 right-shoulder closed-ahead work-zone left_shoulder_closed_ahead 8209 771 left-shoulder closed-ahead work-zone road_construction_ahead

• Identifies location of upcoming road construction.

• This message is an upstream warning

• Roadway Path

• Path ends at point where road construction zone begins

• Should be active in parallel with the associated work zone. 1025 13569 road-construction ahead work-zone road_construction_two_way_traffic

• Identifies section of road where two way traffic is temporarily imposed due to required traffic diversion.

• Roadway Path

• Path starts and ends to cover roadway section where two way traffic is temporarily imposed.

• Active period starts as soon as preparation begins on the roadeay to establish the two way traffic flow.

• Active period ends when all traffic control devices associated with the two way flow have been cleared from the roadway and normal traffic flow is restored. 1025 13593 road-construction both-directions-of-travel work-zone end_road_construction

• Indicates that the vehicle has exited the construction zone.

• This message is downstream from the construction zone.

• Roadway Path

• Path begins within 50 feet downstream from the end of the construction zone.

• Path is between 0.1 to 0.25 miles long

• Should be active in parallel with the associated work zone. 13583 1025 end road-construction work-zone road_construction_congestion_ahead

• Identifies location of heavy congestion ahead due to road construction, with slow moving traffic likely requiring vehicle to reduce speed.

• This message is an upstream warning

• Roadway Path

• Path should end near the end-of-queue even somewhat downstream of end-of-queue is acceptable.

• Path must start upstream from end-of-queue, minimum upstream buffer distance (defined by IOO) from end-of-queue must maintained by updating TIM.

• Active period starts when construction congestion has built up and meets IOO defined traffic slow down thresholds.

• Active period ends when congestion has dropped below IOO defined traffic thresholds.

• The dynamic nature of congestion may require IOOs have have automated queue monitoring and 1025 263 13569 road-construction traffic-congestion ahead work-zone road_construction_be_prepared_to_stop

• Identifies location of likely stopped traffic ahead due to road construction.

• This message is an upstream warning.

• Roadway Path

• Path should end near the end-of-queue or at the location where vehicles stop for the construction site traffic control.

• Path must start upstream from the construction site stop location the minimum upstream buffer distance (defined by IOO). The start location should be upstream from the normal end-of-queue generated by the construction site stop location.

• Active period starts when the work zone stop location is first established on the roadway

• Active period ends when the work zone stop location has been cleared from the roadway and normal traffic flow is restored. 1025 7201 road-construction be-prepared-to-stop speed-limit speed_limit_n_mph

• Identifies the current regulatory speed limit along a section of roadway

• Roadway Path

• Path starts and ends to cover roadway section to which the speed limit applies.

• Active period starts when the IOO initiates the regulatory speed limit on a road section.

Active period ends when the IOO changes the regulatory speed limit or removes the regulatory reduced speed limit. 268

<small number> e.g. 12589 = 45 8720 speed-limit <number> mph speed-limit speed_limit_reduced_n_mph_ahead

• Identifies an upcoming road section that has a regulatory speed limit that is reduced compared to the roadway posted speed limit

• This message is an upstream warning

• Roadway Path

• Path ends at the point where the regulatory speed limit begins.

• Should be active in parallel with the associated reduced speed-limit zone 268 12302

<small number> e.g. 12589 = 45 8720 13569 speed-limit reduced <number> mph ahead speed-limit advisory_speed_n_mph

• Identifies an advised speed along a section of roadway based on IOO criteria.

• May be temporary or permantent advised speed.

• See curve speed warning for advised speed on curves.

• Roadway Path

• Path starts and ends to accurately cover roadway section to which the advisory speed applies.

• Active period starts when the IOO initiates the advised speed and ends when the IOO revokes the advised speed. 7712 268

<small number> e.g. 12589 = 45 8720 advice speed-limit <number> mph traffic-restrictions closed_to_traffic

• Identifies a section of roadway that is currently closed to traffic

• Temporary road closure for any reason, weather conditions, incident, or construction.

• Roadway Path

• Path starts and ends to accurately cover roadway section that is closed to traffic.

• Active period starts when the IOO initiates the road closure and ends when the road is reopened for traffic. 769 closed-to-traffic traffic-restrictions closed_for_the_season

• Identifies a section of roadway that is under seasonal closure.

• Long-term annual, seasonal road closure.

• Roadway Path

• Path starts and ends to accurately cover roadway section that is closed to traffic.

• Active period starts when the IOO initiates the road closure and ends when the road is reopened for traffic. 774 closed-for-the-season traffic-restrictions closed_to_traffic_local_access_only

• Identifies a section of roadway that is restricted to through traffic, but access to local locations from road is available.

• Temporary road traffic restriction for any reason, weather conditions, incident, or construction.

• Roadway Path

• Path starts and ends to accurately cover roadway section that is limited to local traffic.

• Active period starts when the IOO initiates the road traffic restriction and ends when the IOO reopens the road for all traffic. 769 2567 closed-to-traffic local-access-only traffic-restrictions closed_to_traffic_ahead

• Identifies location of upcoming road closure.

• This message is an upstream warning

• Roadway Path

• Path ends at point where road closure begins

• Path starts no more than 2 miles upstream from beginning of road closure.

• Should be active in parallel with the associated road closed to traffic. 769 13569 closed-to-traffic ahead traffic-restrictions truck_restriction_gross_weight_limit_n_lbs

• Identifies a section of roadway that has a gross vehicle weight limit restriction in place.

• Temporary or permanent road weight restriction for any reason.

• Roadway Path

• Path starts and ends to accurately cover roadway section with the vehicle weight restriction.

• Active period starts when regulatory maximum weight truck restriction is initiated.

• Active period ends when regulatory maximum weight truck restriction is removed. 2563 2577

<large number> e.g. 11605 = 60000 8739 truck-restriction gross-weight-limit <number> pounds traffic-restrictions wind_blow_over_minimum_weight_truck_restriction

• Identifies a section of roadway where a minimum weight truck restriction is in place due to high winds and blow over risk.

• Temporary, regulatory minimum weight truck restriction due to high wind blow-over risk.

• Roadway Path

• Path starts and ends to accurately cover roadway section where the regulatory minimum weight truck restriction is in place.

• Active period starts when regulatory minmum weight truck restriction is initiated.

• Active period ends when wind subsides and regulatory minimum weight truck restriction is removed. 5127 2563 2569 7682 2577

<large number> e.g. 11594 = 25000 8739 strong-winds truck-restriction no-high-profile-vehicles below gross-weight-limit <number> pounds traffic-restrictions restriction_no_trailers

• Identifies a section of roadway where a regulatory restriction is in place disallowing vehicles with trailers.

• Temporary or permenant, regulatory restriction on vehicles with trailers due to conditions making trailer traffic hazardous, such as road geometry, road surface condtions, or construction.

• Roadway Path

• Path starts and ends to accurately cover roadway section where the regulatory trailer restriction is in place.

• Active period starts when IOO initiates a regulatory trailer restriction.

• Active period ends when IOO removes the regulatory trailer restriction. 2561 2568 restrictions no-trailers traffic-restrictions chains_required_commercial_vehicles

• Identifies a section of roadway where a regulatory restriction is in place requiring snow chains for all commercial motor vehicles.

• Temporary regulatory restriction due to hazardous road surface traction condtions requiring snow chains for Commercial Vehicles.

• Often referred to as a level-1 Chain Law

• Roadway Path

• Path starts and ends to accurately cover roadway section where the chain law regulatory restriction is in place.

• Active period starts when IOO initiates a regulatory chain law restriction.

• Active period ends when IOO removes the regulatory chain law restriction. 6148 9255 snow-chains-required commercial-vehicles traffic-restrictions snow_tires_or_chains_required_all_vehicles

• Identifies a section of roadway where a regulatory restriction is in place requiring snow tires or snow chains for all vehicles.

• Commercial vehicles must have chains.

• Other than commerical vehicles must have snow tires and all wheel drive?

• Temporary regulatory restriction due to hazardous road surface condtions requiring traction enhancement for all vehicles.

• Often referred to as a level-2 Chain Law

• Roadway Path

• Path starts and ends to accurately cover roadway section where the chain law regulatory restriction is in place.

• Active period starts when IOO initiates a regulatory chain law restriction.

• Active period ends when IOO removes the regulatory chain law restriction. 6156 9217 snow-tires-or-chains-required all-vehicles traffic-restrictions snow_chains_prohibited

• Indicates that the current section of road and beyond no longer requires (and in fact prohibits) snow chains on vehicles.

• Identifies that due to roadway damage caused by snow chains, there is a regulatory restriction to remove snow chains from all vehicles.

• The roadway where this message appears must be free from any snow or ice where chains would be of benefit.

• The roadway where this message appears must have areas where vehicles can pull out of traffic to safely remove chains.

• Roadway Path

• Path starts at point where chains should be removed after a driving through a regulatory chain law area.

• Path is 1 mile long to provide time for driver recognition of new regulatory restriction.

• Active period starts when IOO initiates a regulatory chain law restriction.

• Active period ends when IOO removes the regulatory chain law restriction. 6149 snow-chains-prohibited safety-service-area chain_up_area_ahead

• Indicates an IOO designated area, outside of traffic lanes, where vehicles can stop and apply snow chains.

• Roadway path

• Path starts upstream from chain up area at a distance determined by IOO traffic engineering.

• Path ends upon reaching the designated chain up area.

• Active period starts and ends in parallel with chain law restrictions in the affected area. 6148 11791 13569 snow-chains-required parking-area ahead safety-service-area brake_check_area_ahead

• Indicates an IOO designated area, outside of traffic lanes, where vehicles can stop and check their brake condition before entering a steep downgrade.

• Roadway path

• Path starts upstream from the brake check area at a distance determined by IOO traffic engineering.

• Path ends upon reaching the designated brake check area.

• Typically a permanent active period. 7174 11791 13569 test-your-brakes parking-area ahead roadway-warning right_curve_speed_warning_n_mph

• Identifies location of right/left roadway curve with advised reduced speed.

• Roadway Path

• Path starts upstream of curve at a distance determined by IOO traffic engineering.

• Path ends at the exit of the curve where the advised speed is no longer relevant.

• Active period starts and ends based on IOO determination that curve speed warning is appropriate.

• May be active permanently 13599 7712 8026 268

<small number> e.g. 12579 = 35 8720 right-turn advice on-curve speed-limit <number> mph roadway-warning left_curve_speed_warning_n_mph 13594 7712 8026 268 <small number> e.g. 12579 = 35 8720 left-turn advice on-curve speed-limit <number> mph roadway-warning right_hairpin_curve_speed_warning_n_mph

• Identifies location of upcoming right/left hairpin curve with advised reduced speed.

• Any roadway curve that covers an angle greater than 135 degrees qualifies as a hairpin curve.

• Roadway Path

• Path starts upstream of hairpin curve at a distance determined by IOO traffic engineering.

• Path ends at the exit of the curve where the advised speed is no longer relevant.

• Active period starts and ends based on IOO determination that curve speed warning is appropriate.

• May be active permanently 13617 7712 8026 268

<small number> e.g. 12569 = 25 8720 hairpin-right advice on-curve speed-limit <number> mph roadway-warning left_hairpin_curve_speed_warning_n_mph 13618 7712 8026 268 <small number> e.g. 12569 = 25 8720 hairpin-left advice on-curve speed-limit <number> mph roadway-warning right_winding_curve_speed_warning_n_mph

• Identifies location of upcoming series of linked roadway curves with advised reduced speed.

• Roadway Path

• Path starts upstream of series of curves at a distance determined by IOO traffic engineering.

• Path ends at the exit of the final curve of the series where the advised speed is no longer relevant.

• Active period starts and ends based on IOO determination that curve speed warning is appropriate.

• May be active permanently 13640 7712 8026 268

<small number> e.g. 12579 = 35 8720 winding-road-to-right advice on-curve speed-limit <number> mph roadway-warning left_winding_curve_speed_warning_n_mph 13641 7712 8026 268 <small number> e.g. 12579 = 35 8720 winding-road-to-left advice on-curve speed-limit <number> mph roadway-warning steep_downgrade_n_percent_grade

• Identifies location of a steep downgrade with percent grade specified.

• Roadway Path

• Path covers IOO defined road section with a known, measured steep downgrade.

• Typically a permanent active period. 13589

<small number> e.g. 12550 = 6 8748 8757 hill <number> percent grade roadway-warning steep_downgrade_next_n_miles

• Identifies that there is an upcoming steep downgrade and its approximate length specified.

• This message is an upstream warning.

• Roadway Path

• Path starts upstream of beginning of downgrade at no more than 1 mile from beginning of down slope.

• Path ends where the down slope begins.

• Typically a permanent active period. 13589

<small number> e.g. 12550 = 6 8748 8757 13582

<small number> e.g. 12552 = 8 8712 hill <number> percent grade next <number> miles roadway-warning runaway_vehicle_escape_ramp_1_mile_right

• Identifies an upcoming runaway vehicle escape ramp, on the right/left of the road and its approximate distance ahead.

• This message is an upstream warning.

• Roadway Path

• Path starts approximately 1 mile upstream from the escape ramp start.

• Path ends where it is possible for a run-away vehicle to move out of traffic flow and line up to take the escape ramp.

• Message may alternate with the runaway-vehicle escape ramp closed message during those times when the escape ramp is out of service.

• May be active permanently 9256 8234 12545 8712 13569 7989 runaway-vehicles escape-ramp 1 mile ahead on-the-right roadway-warning runaway_vehicle_escape_ramp_1_mile_left 9256 8234 12545 8712 13569 7990 runaway-vehicles escape-ramp 1 mile ahead on-the-left roadway-warning runaway_vehicle_escape_ramp_closed

• Notifies that an upcoming runaway vehicle escape ramp is closed.

• This message is an upstream warning.

• Roadway Path

• Path starts approximately 1 mile upstream from the escape ramp start.

• Path ends where it is possible for a run-away vehicle to move out of traffic flow and line up to take the escape ramp.

• Activated when IOO confirms that the escape ramp is out-of-service due to runaway vehicle use or other maintainance service.

• Deactivated when IOO confirms that the escape ramp is back in service and available for use.

• Typically alternates with the escape ramp upstream notification message. 9256 8234 770 runaway-vehicles escape-ramp closed traffic-conditions traffic_congestion_ahead

• Identifies location of heavy congestion ahead with slow moving traffic likely requiring vehicle to reduce speed.

• This message is an upstream warning

• Roadway Path

• Path should end near the end-of-queue even somewhat downstream of end-of-queue is acceptable.

• Path must start upstream from end-of-queue, minimum upstream buffer distance (defined by IOO) from end-of-queue must maintained by updating TIM.

• Very fast end-of-queue build up may require IOO have automated queue monitoring and TIM generation/update. 263 13569 traffic-congestion ahead traffic-condtions be_prepared_to_stop

• Identifies location of heavy congestion ahead with stop-and-go traffic likely requiring vehicle to stop.

• This message is an upstream warning

• Roadway Path

• Path should end near the end-of-queue even somewhat downstream of end-of-queue is acceptable.

• Path must start upstream from end-of-queue, minimum upstream buffer distance (defined by IOO) from end-of-queue must maintained by updating TIM.

• Very fast end-of-queue build up may require IOO have automated queue monitoring and TIM generation. 7201 be-prepared-to-stop road-weather-conditions strong_winds_exceed_n_mph

• Identifies a section of roadway with measured wind gusts exceeding limits.

• Temporary warning for measured dangerous wind conditions.

• Determination based on IOO predefined criteria.

• Roadway Path

• Path covers IOO defined road section where wind coditions can be detected, measured, and confirmed.

• Activated when IOO confirms winds exceeding predefined criteria.

• Deactivated when IOO confirms winds have subsided below predefined criteria. 5127 7759

<small number> e.g. 12594 = 50 8720 strong-winds may-exceed <number> mph road-weather-conditions strong_winds_alert_high_profile_vehicles

• Identifies a section of roadway with high winds that significantly increase blow over risk for high-profile vehicles.

• Alert for high-profile vehicles that there is a high-blow over risk due to measured winds.

• Determination based on IOO predefined criteria.

• Roadway Path

• Path covers IOO defined road section where wind coditions can be monitored.

• Activated when IOO confirms winds exceeding predefined criteria.

• Deactivated when IOO confirms winds have subsided below predefined criteria. 5127 9233 6405 strong-winds high-profile-vehicles hazardous-driving-conditions road-weather-conditions slippery_wet_pavement

• Identifies a section of roadway where precipitation has left the roadway wet with reduced traction.

• Warning for vehicles that road condtions may be slick due to known precipitation.

• Determination based on IOO predefined criteria for road surface condtion.

• Roadway Path

• Path covers IOO defined road section where road coditions can be monitored.

• May apply to long multi-mile road sections.

• Activated when IOO confirms road surface conditions meeting predefined traction critera.

• Deactivated when IOO confirms road surface conditions have improved and are close to normal dry road condtions. 5897 5895 slippery wet-pavement road-weather-conditions surface_water_hazard

• Identifies a road section where IOO can confirm significant standing water on roadway.

• Road area with standing water that presents a significant hazard for vehicle hydroplaning.

• Determination based on IOO predefined criteria for road surface condtion.

• Roadway Path

• Path covers IOO defined road section where accumulated water can be confirmed and road coditions can be monitored.

• Typically applies to short road sections where significant standing water occurs.

• Activated when IOO confirms road surface water conditions meeting predefined critera.

• Deactivated when IOO confirms road surface water conditions have improved and no longer pose significant hydroplaning danger. 5893 surface-water-hazard road-weather-conditions dense_fog_ahead

• Identifies location of heavy fog on roadway ahead.

• Required visibility thresholds defined by

IOO.

• This message is an upstream warning

• Roadway Path

• Path should end near the beginning of the dense fog or even some distance into the fog area is acceptable.

• Path starts upstream from fog area where the visibility is good and unaffected by fog. This upstream distance is determined by IOO traffic operations.

• Will require monitoring by IOO traffic operations to ensure upstream warning location remains valid in face of changing conditions.

• Activated when IOO confirms fog accumulation and visibility conditions meet predefined critera.

• Deactivated when IOO confirms visibility conditions have improved and no longer disrupt traffic. 5377 13569 dense-fog ahead road-weather-conditions flooding_ahead

• Identifies location of flooding on roadway ahead.

• Required water level thresholds defined by IOO. Typically more serious than a surface water hazard. IOO responsible to monitor and determine if situation evolves to a road closure.

• This message is an upstream warning

• Roadway Path

• Path starts upstream of flooded roadway at a distance determined by IOO traffic engineering.

• Path ends where flood waters encroch on roadway.

• Activated when IOO confirms road flooding conditions meeting predefined critera.

• Deactivated when IOO confirms road flooding conditions have improved and no longer impede traffic. 1301 13569 flooding ahead road-weather-conditions ice

• Identifies a road section where IOO can confirm significant ice buildup on roadway.

• Limited road area with ice that presents a significant hazard for vehicle traction and control.

• Determination based on IOO predefined criteria for road surface icing condtion.

• Roadway Path

• Path covers IOO defined road section where ice accumulation can be confirmed.

• Path may extend upstream from an isolated ice patch to provide advance warning.

• Activated when IOO confirms road surface icing conditions meeting predefined critera.

• Deactivated when IOO confirms road surface icing conditions have improved and no longer pose significant vehicle traction danger. 5906 ice road-weather-conditions icy_patches

• Identifies a road section where IOO can confirm multiple areas of ice on roadway.

• Multiple, isolated areas of icing, along a longer section of road, are a hazard for vehicle traction and control.

• Determination based on IOO predefined criteria for road surface icing condtion.

• Roadway Path

• Path covers IOO defined roads where multiple icing areas can be confirmed.

• Typically applies to longer road sections with multiple isolated areas of icing contrasting with the more isolated "ice" warning.

• Activated when IOO confirms road surface icing conditions meeting predefined critera.

• Deactivated when IOO confirms road surface icing conditions have improved and no longer pose significant vehicle traction danger. 5907 icy-patches road-weather-condtions severe_weather

• Identifies a road section or area where IOO can confirm severe weather condtions exist.

• Any active severe weather that poses a significant safety hazard for drivers is a candidate for this warning, for example heavy rain, blizzard, or hail.

• Determination based on IOO predefined criteria for weather conditions.

• Roadway Path or Polygon

• Path or Area covers IOO defined roads where severe weather conditions are confirmed to exist.

• Requires real-time monitoring by IOO to update the affected area if the severe weather is moving.

• Activated when IOO confirms severe weather conditions meeting predefined critera.

• Deactivated when IOO confirms severe weather has disapated or has moved outside of IOO area of purview.

Requires real-time monitoring by IOO to ensure timely updates. 4865 severe-weather road-weather-condtions visibility_reduced

• Identifies a road section or area where IOO can confirm visibility is significantly reduced.

• Any active atmospheric condtion that reduces driver visibility. Smoke from fires, blowing dust or sand, or significant haze.

• Determination based on IOO predefined criteria for degraded visibility.

• Roadway Path or Polygon

• Path or Area covers IOO defined roads where driver visibility is reduced.

• May extend outside of area with reduced visibility (upstream or downstream), but should not be more than 1/2 mile outside of the area.

• Requires real-time monitoring by IOO to update the affected area if the visibility limiting condtions are moving.

• Activated when IOO confirms reduced visibility conditions meeting predefined critera.

• Deactivated when IOO confirms visibility limiting conditions have disapated.

• Requires real-time monitoring by IOO to ensure timely updates. 5383 visibility-reduced road-weather-conditions blowing_snow

• Identifies a road section or area where IOO can confirm blowing snow is a hazard for driving.

• Any situation where wind driven snow is a driving hazard due to visibility or snow accumulation.

• Determination based on IOO predefined criteria for degraded driving conditions.

• Roadway Path or Polygon

• Path or Area covers IOO defined roads where the blowing snow hazard exists.

• May extend outside of area of blowing snow (upstream or downstream), but should not be more than 1/2 mile outside of the area.

• Requires real-time monitoring by IOO to update the affected area as it changes.

• Activated when IOO confirms blowing snow conditions meeting predefined critera.

• Deactivated when IOO confirms wind and snow conditions have disapated.

• Requires real-time monitoring by IOO to ensure timely updates. 5385 blowing-snow

CTW Detailed Traveler Information Message Definitions

This Appendix presents the initial detailed definitions developed for TIMs to be used in the CTW effort. In total, 40 different TIMs were prioritized and will be developed for use, and the latest available versions as of publication of this SDD are presented below.

C.1 Advisory Reduced Speed Zone

Version Date Notes

1.0 2025-09-17 Connecting the West Project - initial version

Conditions

Infrastructure Owner-Operators (IOOs) may issue an advisory speed limit to promote driver safety when roadway or environmental conditions temporarily make normal speed limits unsafe. Advisory speed limits are non-regulatory recommendations that alert drivers to reduce speed in response to conditions such as reduced visibility, precipitation, work zones, incidents or traffic congestion.

An advisory speed limit TIM allows drivers to receive up-to-the-minute information about recommended speeds on the highway. This can encourage safer speeds for specific road sections based on the IOOs information about conditions and performance on their roadway network. IOOs may determine and deploy these advisory limits manually or through automated systems that respond to real-time data from roadway sensors, weather information, or connected vehicle inputs.

This general advisory speed limit TIM is used when the IOO needs to recommend a safer driving speed in response to changing or temporary roadway conditions. Other types of TIMs address reduced speeds for specific situations—for example, a curve speed warning TIM provides an advised speed for navigating curves. In work zones, however, reduced speeds are often regulatory rather than advisory; in those cases, a regulatory reduced speed limit TIM should be used instead.

Message

The intent of this message is to warn drivers that due to current conditions on the roadway a reduced speed is advised. The advised new speed is included in the message. This message follows the recommended ITIS phrases for advised reduced speed, as shown in the table below.

The suggested visual display icon matches the MUTCD signage for an advisory speed.

Standard message phrase and ITIS codes Suggested drivers display icon

Advice, speed-limit, <number>, mph

7712, 268, <small number e.g. 12599 = 55>, 8720

Geofence Extent The geofence should align with the section of roadway where the advisory speed applies. It should start and end coincident with the boundaries of the advised speed section.

Key points of the advisory speed zone TIM geofence:

● Point A: beginning of the road section affected by the advisory speed limit

● Point B: end of the road section affected by the advisory speed limit

● Point C: start of warning TIM for the advisory speed limit (upstream)

● Point D: end of warning TIM for the advisory speed limit geofence (downstream)

● Width E: width of the TIM geofence

The geofence start and end locations, width, and the path of the roadway determine the shape, length, and direction of the TIM geofence.

Start to End Extent

The TIM geofence should cover the entire length of the road section subject to the advisory speed limit. The start of the TIM geofence (Point C) should be coincident with the start of the advisory speed road section. The end of the TIM geofence (Point D) should match the end location of the advisory speed road section

Width Extent

The defined width of the geofence should encompass the entire roadway in the specified direction. The width should not extend significantly beyond the edge of the roadway, as this may cause vehicles on parallel service roads to consider the TIM as relevant for them.

Opposite Direction Consideration

For a two lane, bi-directional road, it is likely that the advised reduced speed will apply to both directions of travel. In this case a single TIM can be created with a geofence width that covers the full width of the roadway. The directionality for this TIM path can be set to “both” making the TIM applicable for vehicles traveling in either direction.

On a divided highway, the advised reduced speed may only apply to one direction of travel. In this case a single TIM with a geofence covering the lanes in the affected direction should be created, with a directionality matching the travel direction.

A

B

D

C

E

An advised reduced speed due to weather conditions will likely apply to both travel directions on a divided highway. In this case two separate TIMs should be created, one for each travel direction since the geofences for these TIMs need to be tailored to the roadways in each direction.

Timing If the advisory speed is activated for a planned period, then it will be possible to specify an end-time for the TIM. For those situations where the advisory speed is initiated for a dynamic situation, the end-time may not be known. In these cases, the TIM end-time can be set to indefinite. However, if possible, an end-time should always be specified even if it is an estimate. An estimated end-time can be updated with a revised, accurate end-time as soon as better information becomes available.

C.2 Be Prepared to Stop

Version Date Notes

1.0 2025-09-19 Connecting the West Project - initial version

Conditions

Events that significantly disrupt traffic flow, creating queues and causing vehicles to stop unexpectedly, can lead to crashes if not communicated to approaching drivers. There are multiple conditions that can result in stop-and-go or completely stopped traffic. Excessive traffic volume can cause recurrent stop-and-go congestion at some roadway locations. An accident, especially during a high-volume period, can restrict traffic flow and lead to congestion propagating upstream. Localized severe weather such as hail or a downpour can slow and stop traffic; producing a queue that propagates upstream from the weather affected area. Planned events such as road construction may also restrict traffic flow causing upstream queues. A construction site with reduced lanes restricts traffic flow, often generating a bottleneck with stopped traffic. A road construction site with a flagger or a traffic signal controlling alternating direction traffic on a single lane will stop traffic at both ends of the alternating traffic flow lane. In all these cases, drivers approaching from upstream may not be aware of the stopped traffic and as a result may brake sharply or quickly switch lanes, behavior that significantly increases the chance of an accident.

This stopped traffic TIM might be used by itself to warn of the hazardous downstream traffic conditions or used in conjunction with other TIMs such as “incident ahead” or “lane blocked ahead” to better inform the driver/vehicle about the imminent traffic conditions.

This “be prepared to stop” TIM should be used when traffic flow has slowed to the point where upstream drivers must stop when they reach the congestion. This TIM indicates more severe congestion conditions than the related “congestion ahead” TIM. IOOs will need to develop appropriate metrics to distinguish between the use of these two TIMs.

Traffic congestion is dynamic. A congestion TIM with a one-mile upstream extent from the current end-of-queue location may be overwhelmed in only a few minutes if the incoming traffic volume is heavy. IOOs must assess their systems and processes to ensure messages can be updated at a tempo necessary to keep the messages ahead of the developing congestion.

Message This message warns drivers that there is stopped traffic ahead of them and they should monitor downstream traffic for slowing or stopped traffic. The ITIS phrase “be-prepared-to-stop” conveys this information. Adding the “road-construction” phrase as a prefix provides further information that the stopped traffic is due to road construction and some type of traffic control might be expected. The suggested in-car display icon follows MUTCD standard shape and color scheme for incident or construction related warnings.

To be useful it is important that this TIM be provided to drivers before they reach the area requiring them to slow down and stop.

Standard message phrase and ITIS codes Suggested driver display icon be-prepared-to-stop road-construction, be-prepared-to-stop

1025, 7201

The geofence extent for this TIM is defined relative to the location of the stopped traffic on the roadway.

This stopped traffic area is defined by the boundaries of the slow moving or stopped traffic (see Points A and B in the diagram below). Due to the dynamic nature of congestion, this area will evolve over time.

The upstream propagation rate for the traffic end-of-queue will determine the processes or systems required by the IOO to generate and maintain effective stopped traffic warning TIMs.

To provide effective warning to drivers, the geofence extent for this message must start upstream from the congested, stopped traffic area. This upstream warning distance (Point C to Point A in the diagram below) determines the advanced notice provided for approaching drivers. Due to congestion being dynamic it may only be possible to maintain a general range for this upstream distance. The following guidelines suggest some ranges for this advanced warning distance based on the posted speed limit of the affected roadway. IOOs will need to define these distance ranges appropriate to their traffic environments.

Roadway posted speed limit (mph)

Range for advanced warning distance (miles)

< 50 0.25 – 1.0

>= 50 0.5 – 2.0

Since this TIM is intended to be an upstream warning, it is important that the start of the geofence (Point C) is maintained an appropriate distance upstream from the stopped traffic end-of-queue. There is also a general constraint on the TIM geofence end location (Point D). The end of the geofence extent should always be located within the congestion zone; that is at or downstream of the stopped traffic end-of-queue (Point A) and upstream from the congestion end (Point B).

To generate reasonable geofences for congestion warning TIMs, IOOs will have to assess the ability of their traffic monitoring systems to identify and locate areas of congestion. The key information produced by the traffic monitoring systems will be boundary locations for the congestion, the upstream end-of-queue (Point A) and downstream end (Point B) of the congestion zone. Rapidly changing congestion will require that IOO’s traffic monitoring systems be capable of continuous monitoring and tracking of these congested zone boundaries.

For example, if a stopped traffic warning TIM is created with an upstream warning distance (Point C to Point A) of 1 mile, but the congestion end-of-queue (Point A) is propagating upstream at a rate of 3 miles-per-hour, the initial stopped traffic warning TIM will be useless within 20 minutes. In this example, refreshing the TIM every 10 minutes with an updated geofence extent based on the current end-of-queue location, would maintain the geofence start point ½ to 1 mile upstream of the stopped traffic and keep this TIM effective.

Key points of the “be prepared to stop” TIM geofence are:

● Point A: approximate location of the stopped traffic end-of-queue (if available automatic detection may be able to track this)

● Point B: end of the congested area (location may be only roughly determined unless there is some road event that is the source of the congestion)

● Point C: start of the “be prepared to stop” TIM geofence

● Point D: the end of the “be prepared to stop” TIM geofence

● Width E: width of the TIM geofence

The geofence start and end locations, width, and the path of the roadway determine the shape, length, and direction of the TIM geofence.

Start to End Extent

The relevant area to warn drivers with this message is upstream of the stopped traffic area. Therefore, the start point of the geofence (Point C ) should be located some distance upstream of the congestion end-of-queue (Point A). The suggested logic outlined above locates the geofence start point within a range of distance upstream from the stopped traffic area based on the posted speed limit of the roadway. The logic locating the upstream start point should also account for any constraints that may limit the upstream distance.

The geofence end point (Point D) should fall within the congested zone (Point A to Point B) and should be preferably located closer to the end-of-queue (Point A) rather than the end of the congested zone (Point B). In a dynamic situation, with moving congestion zone boundaries, the geofence start and end points may only be roughly determined subject to the above-mentioned constraints.

Width Extent

The geofence width should encompass the entire roadway. For a bi-directional two-lane road, it does not matter if the width extends into the opposite direction lanes as the start and end points of the geofence define the travel direction for the TIM. This direction of travel is included in the path “directionality” encoded within the TIM. The TIM directionality limits the TIM relevance

A

B

E

D area to only those vehicles whose direction of travel aligns with the defined directionality.

Opposite Direction Consideration

Each direction of a divided highway hosts different traffic flows, so traffic congestion occurs in each direction independent of the other. Due to the independent traffic flows, unique TIMs should be created for each roadway direction.

An event causing stopped traffic on a two-lane bi-directional highway will likely affect both travel directions. Given the differences in geofence extents and traffic conditions for each travel direction, two separate TIMs should be created for this roadway situation as well.

Timing

A stopped traffic warning TIM should be activated as soon as the congestion buildup is detected and an approximate location for the end-of-queue is determined. The stopped traffic TIM should be deactivated when continuous traffic flow is restored. There may be a transition period where traffic is no longer stopped but there is lingering congestion and a “congestion ahead” TIM could replace the stopped traffic

TIM.

A critical timing element for a stopped traffic TIM is the update rate necessary to keep the TIM relevant as an upstream warning. The simplest timing is to create a TIM when the congestion event is first recognized and end this TIM once the event and queue have cleared. This simple timing, creating a TIM and not updating it, is only feasible for stopped traffic events that have a limited queue propagation. For example, a cyclical queue at a road construction site or a blockage event with limited traffic volume. More dynamic stopped traffic events will require a regular update process to maintain the location and timing accuracy of the message. This regular update process may require automated detection systems to identify and track the end-of-queue location. Active TIMs for dynamic stopped traffic events will need their geofence extent and end times revised with a regular cadence to maintain an effective message.

C.3 Blowing Snow

Versio n

Date Notes

1.0 2026-01-27 Connecting the West Project - initial version

Conditions

Blowing snow creates significant safety hazards for both passenger and commercial vehicles by reducing visibility, sometimes to whiteout conditions, which limits drivers’ ability to see lane markings, road edges, and stopped or slow-moving vehicles. For passenger vehicles, the primary risks include loss of traction, sudden skidding and overcorrection by less experienced drivers, all of which increase the likelihood of spinouts and multi-vehicle collisions. Commercial vehicles face different but serious hazards, including longer stopping distances on icy surfaces, reduced maneuverability, and a heightened risk of jackknifing or rollover due to high vehicle profiles and strong crosswinds. Snow plumes generated by large trucks can further obscure visibility for surrounding traffic, increasing the chance of chain-reaction crashes.

Overall, blowing snow elevates crash risk for all vehicle types by combining poor visibility, unpredictable road conditions, and limited reaction time.

When determining whether to issue a blowing snow TIM, IOOs must assess the combined effects of wind and falling or existing snow, which together create the distinct hazard of blowing snow. Information from automated weather detection systems and field reports should be used to evaluate roadway conditions, with a primary focus on visibility reductions that impact driver awareness and reaction time. Based on these observations, IOOs should define clear thresholds that indicate when blowing snow conditions pose a safety risk. These thresholds may vary by location, and IOOs should tailor them to align with state-specific safety objectives, roadway characteristics, and operational practices to support timely and consistent traveler information for blowing snow conditions.

Message This message is a warning, not a regulatory restriction. Its purpose is to alert drivers that blowing snow may significantly impact visibility and safety. Drivers should adjust their driving behavior accordingly, including reducing speed, increasing following distance, or possibly exiting the highway if conditions worsen.

The standard ITIS phrase “blowing-snow” is used for this message. The suggested driver display icon uses the diamond shape and coloration following standard MUTCD roadway and weather-condition warning signs.

Standard message phrase and ITIS codes Suggested driver display icon blowing-snow

Either a road-path geofence or an area geofence may be used for blowing snow TIMs. A road-path geofence is most appropriate in areas where one or two major roadways traverse the affected region and nearly all motorist traffic is confined to those routes. In contrast, an area geofence—defined by a polygon or a point-radius circle—is better suited for locations with dense roadway networks, where applying a single area-based geofence can reduce the need to generate and maintain multiple TIMs on individual roadways. The boundaries for the affected area may only be roughly known, and an area based geofence can overlap a large area to provide warnings for all vehicles within the defined boundary.

Because the boundaries of…