Transit Signal Priority

Getting things done is not just a productivity method for office workers, it’s also the way transport works. Vehicle-to-everything (V2X) is the best technology to make the most out of road capacity and prioritize certain tasks.

V2X provides two-way communication between vehicles and intelligent transportation systems on a dedicated channel to enable advanced traffic services. Normal vehicles benefit from receiving lane-by-lane information on the status of traffic lights. Authorized vehicles can do more than that, they can request a green light to move through intersections quickly.

When you add up the seconds that vehicles do not spend waiting at traffic lights, the gains in travel time and reduced fuel consumption are significant.

Transit Signal Priority has obvious benefits for emergency services because every second counts in saving lives. For other public services, such as garbage collection and snow removal, getting the job done quickly means less disruption to traffic. Snow removal is also a life-saving effort as more drivers can enjoy improved road conditions. When it comes to public transport, bus priority supports important public welfare initiatives.

Bus lanes give priority to public transport along the entire length of the road – where there is space and money to build them. TSP provides a priority at intersections, and the necessary equipment is much easier and cheaper to install.

V2X helps reduce congestion, increases equality in transport, and active forms of mobility can be integrated into the feeder network, which contributes to better air quality.
V2X helps reduce congestion, increases equality in transport, and active forms of mobility can be integrated into the feeder network, which contributes to better air quality.

Planning for the future

V2X technology is technically superior to legacy optical TSP systems, as it doesn’t require line of sight, and it operates in snow and rain on a radio frequency dedicated to road safety. But that is not the most important thing. V2X brings a revolutionary transformation to traffic management, allowing Infrastructure Owners and Operators to improve overall traffic conditions and pay special attention to the needs of the public, including reliable public transport and outstanding emergency services.

V2X will also be deployed on cars and bicycles. The popularity and rapid spread of V2X ensures that once you install a V2X roadside unit, it can be used in multiple ways to exploit its full potential with additional advanced services. Road managers can even see and analyze traffic based on the information they receive from connected vehicles. That’s the power of V2X.

Commsignia is the largest V2X-focused company and a key member of global organizations working to standardize the technology. We provide hardware and software, including our own security stack, and professional services to cities, road operators, carmakers and bicycle OEMs to help build up the global connected vehicle ecosystem in which every road user benefits from V2X technologies

Get in touch with us to learn more about V2X technology and our TSP solutions.

Denver chose V2X to move snow plows faster

In the mountainous state of Colorado, clearing snow-covered roads is one of the toughest challenges – in the state capital, the white blanket can sometimes be as thick as 50 inches.

Denver has sought to improve the situation with advanced vehicle-to-everywhere (V2X) technologies. They worked with Commsignia to build V2X coverage, so V2X-capable snow plows can request free passage at intersections, allowing trucks to clear roads with minimal disruption to traffic.

In Denver, more than 100 intersections are now covered with Commsignia’s Roadside Units (RSUs) to provide Traffic Signal Priority (TSP) services.

Vulnerable Road User Protection

Everybody wants predictable and safe travel options

Building a safer physical road infrastructure requires a huge investment, and agencies often apply for public funds to implement their plans. Thanks to funds such as the SMART Grant, these efforts can be combined with digital solutions to achieve more impactful and longer lasting improvements.

One of the easiest ways to upgrade an intersection is to install a modern Traffic Light Controller, connect it to the network, and add state-of-the-art Vehicle-To-Everything (V2X) technology. With the V2X in place, cities and other infrastructure owners and operators (IOOs) can upgrade their vehicles fleets with connectivity and use a range of safety and efficiency features to prevent traffic conflicts and protect vulnerable road users. Even at intersections, where the most complex interactions occur.

Commsignia is working with carmakers, bicycle manufacturers and mobile network operators to build up the operating system of connected traffic. This means, for example, installing V2X on cars and bicycles and providing data management tools to IOOs, putting an emphasis on interoperability with existing TMC tools.

But the roll-out of V2X on vehicles is gradual. We cannot expect all cars, pedestrians and cyclists to be equipped with V2X devices that actively communicate with the cloud or the TMCs – at least not all at once. 

It’s very important to focus on non-connected vulnerable road users, digitizing them with the help of sensors.

Commsignia works with many sensor provider companies such as Bosch, Teledyne, Smartmicro or Velodyne to integrate their cameras, lidars, radars and other devices with our V2X roadside units. V2X is a future-proof road safety investment that provides instant access to advanced traffic services. 

Not only for VRUs

One example of such advanced service is the Transit Signal Priority (TSP) and Green Light Optimal Speed Advisory (GLOSA) application. At first glance it may seem like an optimization, a mobility service. Sure, it will optimize traffic, as TSP with V2X can help buses, ambulances, fire trucks and urban maintenance fleet vehicles move through signalized intersections faster by providing them a green wave. It also helps reduce operating costs.

An independent study made by the Virginia Tech states that GLOSA brings about 22.1 percent saving on fuel and 6.1 percent less travel time.

Optimization often comes with indirect safety benefits. When snow plows with priority do their job faster, fewer people will travel on slippery roads. Garbage trucks cause less disruption in traffic, and less frustration in drivers, so they will keep focusing on driving. And here’s a very obvious one: prioritized ambulances get to the injured people faster, which can truly save lives.

The same priority service can also be a practical tool in supporting VRUs. It can be used to automatically switch to a free crosswalk signal, or maintain a longer signal for safe crossing when sensors detect people on the pavement. V2X performs particularly well in special traffic situations where VRUs are involved. It is worth cooperating with road maintenance companies and local institutions to exploit the potential of V2X. It is possible to set up temporary speed limits when kids arrive at school, and when there are actually people busy in a road work zone. 

Commsignia enables urban fleets retrofitted with V2X, such as ambulances and snow plows, to receive these notifications in the same way as V2X-equipped cars and bikes.

It is always a matter of careful planning to ensure that the V2X infrastructure is set up correctly and does not cause disruption elsewhere. Commsignia Central data and device manager platform can provide insights into potential conflict zones to help planners in optimizing traffic and improving the built infrastructure where it is most needed.

At Commsignia, we are committed to improving mobility for all by providing our partners with cutting-edge innovative V2X software, hardware and services. To find out more about the endless potential of a connected ecosystem and V2X technology click here to contact us today. 

Off the shelf features of V2X

  • connected urban fleets receive alerts about VRUs nearby
  • works without a line-of-sight on a radio frequency dedicated to road safety
  • integration with traffic light controllers used in the US
  • easy deployment, installation and maintenance
  • V2X-enabled vehicles can be notified of 
    • changes in road conditions, when weather makes driving dangerous
    • objects or stationary vehicles on the road
    • emergency braking multiple cars ahead in the same lane so drivers can slow down instead of hard braking

Work Zone Safety
Virginia Case Study

Protecting pedestrians and bikers on the roads is a particularly important topic in the area of vehicle communications, and innovative car manufacturers like Audi are recognizing that V2X technologies allow them to prevent collisions with vulnerable road users – especially in road work zones. In addition to safety V2X allows drivers to enter intersections more confidently, knowing in advance when the traffic lights turn red.

Commsignia and Audi are collaborating with Qualcomm, American Tower Corp., Virginia Tech Transportation Institute (VTTI), Traffic Technology Services, and the Virginia Department of Transportation (VDOT) in deploying cellular vehicle to everything (C-V2X) devices on the Virginia Smart Road to improve work zone safety, offer new services to customers and develop new business models with public and private sectors involved.

Traffic signal information use case is building on Audi’s already established Traffic Light Information (TLI) service, that shows the time until the lights turn green. The new roadside infrastructure is sending low latency C-V2X messages to the Audi Q8 SUVs and warns drivers about an imminent red-light violation.

Improved visibility in work zones

The vulnerable road user (VRU) use case is focusing on a specific group of pedestrians, road maintenance workers. Safety messages are sent both ways. Roadside personnel in the construction zone were equipped with C-V2X-enabled vests that warned them of the approaching Audi Q8 SUVs outfitted with C-V2X onboard units, and the vehicles also received alerts about VRUs nearby.

Commsignia contribution

Commsignia supplied C-V2X enabled ITS-RS4 roadside units and ITS-OB4 onboard units for the project.

The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.
The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.

Onboard traffic light information is useful for drivers in case they don’t see the lights well due to harsh weather conditions.

V2X message types used in this project:

MAPcontains information about the lanes in the intersection
SPaTSignal Phase and Timing, gives information about the traffic light statuses
TIMTraveler Information Message (DENM in Europe), contains information about road and traffic related issues
BSMBasic Safety Message, describes the vehicle
PSMPersonal Safety Message, similar to BSM, but reporting about humans and animals


Vehicles equipped with C-V2X can receive low latency warnings about hazards recognised by the digital road infrastructure. It’s an ongoing project, and the roadside units deployed act as enablers for autonomous driving functions. The Virginia Smart Road project was well received by the U.S. media.

Predictable Transportation
West Midlands Case Study

Transportation is quickly evolving, and the industry is looking for innovative ways to make the delivery of goods safer, faster and more predictable. The Midlands Future Mobility consortium is based in the West Midlands, the hub of car manufacturing and automotive technologies in the UK, and has built the testbed for connected and autonomous vehicles (CAVs) and intelligent transport systems to evaluate new technologies.

Transport for West Midlands sub-contracted Siemens Mobility who have been working closely with Commsignia since May 2020 to install CAV infrastructure on the Midlands Future Mobility route, over 300 kilometers of urban, rural, suburban and highway roads. The region’s automotive sector will trial, develop and deploy technology on the route, for example utilising data to trigger warnings about traffic and road hazards. In the future autonomous vehicles will also be trialled, closely monitored by operators.

Fully integrating Public Key Infrastructure (PKI) into the devices guarantees secure communication between the Roadside Units (RSUs) and the device management. Safety is a basic requirement in the project as the trials are running on public roads.

Commsignia contribution

Commsignia supplied roadside units to the project’s multi-vendor environment, connecting the RSUs with device management developed by Siemens Mobility.

The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.
The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.

The project is among the first deployments in Europe to integrate CAV infrastructure with security PKI in order to establish fully secure communication on the V2X interface.


The Midlands Future Mobility project paves the way to improve air quality, reduce congestion and integrate ridesharing services to the public transport services. It’s also the infrastructural foundation of the region’s planned responsive, flexible and predictable goods delivery system that will be based on autonomous pods and carriers.

Support for Self-Driving Vehicles
Las Vegas Case Study

Las Vegas is a city with intense tourism, and visitors typically wander around the downtown by foot, being unfamiliar with local transport environment, with their attention divided. The City puts great emphasis on making its roads safe for the most vulnerable road users, and was looking for a future-proof solution to lay the basis of intelligent transport and preparing for the autonomous era.

In late 2017, Las Vegas also launched the very first driverless shuttle on a public street in America. Members of the public can take free rides on a 12-seater Navya self-driving shuttle along a 0.6 mile loop that includes the city’s iconic Fremont Street. Making sure it has a smooth ride was a key priority.

Commsignia contribution

Commsignia’s roadside units (RSU) were installed along the Las Vegas Strip and other critical infrastructure points in the Las Vegas Innovation District such as traffic intersections, roundabouts and busy roads.

The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.
The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.

Working with the local partner, Southwest Traffic Systems, Commsignia supplied its next generation Smart City ITS-RS4 Roadside Units as part of the infrastructure to support the driverless shuttle at junctions and other critical points along the route.

The ITS-RS4 acts as a local hub for sensor data exchange as well as a service/application platform that can be used to enhance the safety of all road users and help optimize traffic management. The ITS-RS4 gathers information from the surrounding environment such as traffic cameras, traffic light controllers, sensors and V2X connected vehicles – cars, motor-cycles and even bicycles. A powerful Deep Neural Network / GPU accelerated Artificial Intelligence processor creates a real-time representation of the information to create a dynamic model of the environment.

Applications and services in the ITS-RS4 utilize the dynamic model to enhance road-safety generating real-time alerts to drivers, connected autonomous vehicles and pedestrians, whilst escalating events and aggregated data for analytics to Traffic Management Centers.


The deployment is one of the largest smart city deployment in Northern America to date.The infrastructure has been operational for 2 years and counting, with no major hardware failure. The cooperation has been since expanded, Commsignia’s RSUs now cover more than 300 intersections. The driverless shuttle carried over 30,000 passengers in its first 11 months of operation.

Connected Autonomous Vehicles
San Diego Case Study

In August 2020, the San Diego Regional Proving Grounds — a U.S. Department of Transportation designated regional test-bed for highly automated and self-driving vehicles — Caltrans, the San Diego San Diego Association of Governments (SANDAG) and other local agencies launched a pilot project to evaluate C-V2X technology as part of a connected roadside infrastructure, and to assess how it can support the widespread deployment of intelligent transport solutions.

The project covers a 3-mile stretch of highways and traffic light intersections off Interstate-805 and State Route 52 between Sorrento Valley and Kearny Mesa. It also includes vehicles equipped with onboard units (OBU) and roadside units (RSU).

During the pilot, infrastructure-to-vehicle (I2V) TIM messages are being sent out, covering reduced speed zone, work zone and disabled vehicle. With the expansion of the pilot, the implementation of SPaT is also planned.

Commsignia contribution

Commsignia contributed to the project by supplying
C-V2X enabled ITS-RS4 roadside units.

The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.
The C-V2X ITS-RS4 platform provides a precise digital map of the intersection and traffic light timing information for each lane.

It features the latest cyber security measures including Hardware Security Modules (HSM) and V2X Software Stack to make sure that the system adheres and exceeds latest security standards.
The ITS-RS4 platform builds on the market leading and proven V2X Software stack supporting applications including

  • V2V for vehicle collision avoidance and safety systems;
  • V2I for enhanced traffic signal timing and priority;
  • V2N for real-time traffic routing and cloud services;
  • V2P for safety alerts to pedestrians, cyclists and motor bikes.


The pilot is still ongoing, the experience gained will support transportation planning efforts of the region.