Active Traffic Management (ATM) Signs
In March 2020, the Nevada Department of Transportation (NDOT) introduced 42 Active Traffic Management (ATM) signs along Interstate 15 and U.S. Highway 95 in the Las Vegas valley. The signs were installed as part of Project Neon, which widened and reconfigured the state’s busiest stretch of freeway.
The full-color LED signs provide next-generation, real-time driver information to prepare motorists for upcoming incidents that prompt lane closures or restrictions.
What are ATM signs?
The ATM System is a strategy adopted by NDOT to maintain safe travel by warning drivers of upcoming lane closures due to construction or crashes. Motorists have the opportunity to react well before they reach the incident, cutting down commute times and greatly reducing the potential for secondary crashes.
Secondary crashes occur when inattentive drivers do not react to slower or stopped traffic. They often pose a greater chance of injury than the initial crash – about 17 percent of fatalities are caused by secondary crashes.
ATM signs communicate with motorists in real time, informing them when to merge prior to reaching the point where an incident has closed the lanes.
How do they work?
Overhead symbols indicate whether a lane is open or closed and alert drivers to begin merging to avoid congestion during an incident on the freeway. Overhead message signs accompany the symbols and warn motorists of backups and collisions ahead.
What you need to know …
- Digital speed limit signs appear on the right-hand side of every ATM sign and can be adjusted to a lower enforceable speed limit when traffic slows. This important safety element discourages motorists from weaving in and out of traffic at higher speeds, reducing the potential for crashes.
- High Occupancy Vehicle (HOV) signs, located on the left side of the gantry, allow NDOT to open the HOV lane to general traffic when at least two lanes of general traffic are closed. To keep traffic flowing, the HOV signs will change to read “Open to All.” In that case, vehicles with one occupant will be permitted to use the lanes and legally cross the double white lines.
- Lane control arrows and X’s (located above each lane) will be activated based upon roadway conditions, traffic demand and incidents; otherwise they will remain dark.
- If motorists need to proceed with caution, a yellow “X” with the word “Caution” will appear above the lane.
- If motorists must prepare to merge from a closing lane, a yellow “X” with the word “Merge” will appear above the lane.
- If the lane is closed to traffic, a red “X” with the word “Closed” will appear above the lane.
- Once motorists have passed the incident and all travel lanes are open, they will see a green arrow with the word “Open” above the lanes.
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CLICK HERE to download a ATM Fact Sheet