Variable Speed Limit (VSL) system comprises several VSL signs and connected detectors for measuring traffic situation. VSL shows some speed limits, based on the perceived traffic state adjacent to the sign and the traffic state both upstream and downstream.
Variable speed limits were first launched in the 1960s. In the 1970’s it was introduced as a motorway traffic control system. The system boasts of two major outlooks that are adversely defined.
The two major perspectives in the outlook are defined as follows:
- Homogenization systems that avert traffic congestion by applying minimized speed limits when traffic flow is in near-capacity to prevent unstable traffic situations.
- Incident detection systems enhance safety by enforcing the speed limit instantly in case of incidents, thus, minimizing the possibility of more incidents.
Benefits of Variable Speed Limit Systems
Variable speed limits disposals can regulate traffic and enforce efficiency and safety. Because variable speed limit systems have different formation goals and correlating system design, differing benefits are realized.
Speed homogenization forecasts normally apply basic algorithms from real-time traffic to report safety improvements and natural road conditions.
Projects that involve Active Traffic Management (ATM) systems relay practical mobility data for the safety of workers and motorists.
Variable Speed Limit Systems benefits differ from location to location. It is challenging to provide conclusive discrepancies causes; because of several uncontrollable factors found in various sites, for example, road geometry, driver’s conduct, and compliance rate.
The following are benefits of VSL systems benefits:
1. Provide Safer Speeds in Work Zones
Many agencies have come up with the idea that carrying out nighttime construction minimizes and lessens congestion and traffic queues in comparison to daytime work. The lower the low number of vehicles, the higher the chances of speeding, which poses a grave danger in work zones.
VSL system enforces speed limit of vehicles approaching work zone areas, thus cars pass through at safe speeds. It uses real-time traffic information to provide information for road safety and coordinates the flow of traffic by minimizing speed differences, amid vehicles covering lanes; in the same lanes; between downstream and upstream traffic passages.
2. Seamless Traffic Flow and Minimal Delays
VSL units manage vehicles’ speeds to enhance traffic flow and promote safety. Seamless traffic flow and minimal delays is realized through:
- Short traffic queues
- Minimal congestion
- Quick accident clearance
- Fewer vehicle crashes
Data from VSL shows: vehicle counts, occupancy per lane, and speed of each vehicle. It also shows the history of lane changes and each lane set speed.
VSL promotes traffic flow by applying vehicles’ speed limit when there is an ongoing road construction ahead. It also makes it easy for cars to change lanes by running speed distribution across lanes.
3. Capability to Relate to Road Weather Information Systems (RWIS) To Minimize Speeds During Cold Climate.
VSL units can process weather information for the benefit of the road user. Due to this, many agencies install VSL systems.
Weather optimized VSL unit is utilized when weather conditions like fog and ice affect drivers’ driving ability and vehicle performance, which causes delays. Some agencies integrate RWIS stations with these systems to provide the information needed, which is useful in deciding when speed limits should be lessened during unfavorable weather conditions.
VSL implementation during unfavorable weather improves road safety and promotes traffic efficiency. Motorists get informed about the situation of the road ahead and get calls for action.
VSL Units Key Challenges
Implementing a VSL system is no easy task and comes with challenges, such as the enforcement of varying speeds, setting of speed limits, and driver comprehension of the system.
There are various systems installed across the country, and they can be different and unique, with divergent characteristics and performance. The following can be some of the challenges experienced by states in the running of these units:
- Recruitment of experienced staff with broad capabilities to manage VSL systems
- Maintenance of reliable and nationwide communication
- Coming up with methods that encourage compliance to VSL signs
- Generating public consent via outreach activities
- Lack of valuable data to hold- up VSL system rationale
- VSL hardware and software failures
- Lag in data that results in delayed information for setting road speed limits
Order Signage from Work Safe Traffic Control Industries
Work Safe Traffic Control Industries, in collaboration with local governments, heightens safety and reduce traffic congestion on roads. The company manufactures VSL systems specifically intended for highways and roads and can be sourced by local municipalities, state government, city government, state highway department, road management departments, and local contractors as well. All of our signs are manufactured per the Manual on Uniform Traffic Control Devices.