Connected and autonomous vehicle technologies have the potential to change transportation on a global scale. They can improve safety, significantly alter transportation costs, change traffic patterns and congestion, drive job creation, talent retention, and strengthen our communities’ quality of life.
The implementation of CAVs is a big opportunity for economic development. Still, it also poses important questions about how to maximize the technology’s benefits to social welfare while mitigating negative externalities. Studies show that even partial implementation could have dramatic impacts on our transportation infrastructure and travel patterns.
Although the full deployment of CAVs remains years away, it is time, therefore, for government officials, planners, and economic developers to begin preparing for the potential impacts of this transformative technology and to carefully consider how the potentially substantial changes may dramatically change transportation, infrastructure, and land use.
The local agencies need to plan the most likely scenarios for CAVs in the next 10 to 5 years, including gradual integration of autonomous technology, truck platooning, and the critical infrastructure needs like pavement markings, signing, traffic signals and communication infrastructure, high-resolution mapping of roads, maintenance, consistency and standardization of rules, etc.
In this post, we briefly present some of the key recommendations that government and road agencies should consider as part of autonomous vehicles readiness and prepare for the potential policy and implications of CAVs.
1. Pavement markings
Current CAV systems use cameras and image processing to identify lane markings to the road alignment and locate the vehicle within the cross-section of the road. Several demonstrations of autonomous vehicles have failed due to the overlapping and inconsistent pavement markings, making it difficult for the sensors to predict where the vehicle is in the lane, causing the vehicle to rely on other features such as the edge of the roadway. This underscores the need for consistency of markings for current advanced driver-assistance systems (ADAS), and lane-keep assistance (LKA) to decipher the road surface and keep a vehicle positioned within its lane.
Therefore, road agencies should track how autonomous vehicle manufacturers are handling CAV lane-keeping technology. The direction in which the CAV lane-keeping technology goes will impact pavement marking policies, signage development, and rehabilitation, which will cost road agencies more in maintenance costs. The popular recommendations are as follows:
- Create national standards and guidance on pavement markings and standards that will include minimum criteria of a 6-inch edge, lane, and center lines with a retro-reflectivity level of 35 mcd.
- Develop a high contrast and high retroreflective pavement marking tape or liquid pavement markings with 3M Optics that make markings more visible in the rain or other low-visibility conditions.
- Update and maintain good-quality, consistent, and uniform lane markings.
- Place lane lines immediately after constructing or resurfacing roads.
All CAVs use optical cameras for sign recognition. The machine-vision systems capture an image, such as a street sign, and then classify the sign using feature extraction and matching. Similar to pavement markings, current CAV systems are confused by damaged, faded, or non-compliant signs. CAVs require signing to be consistently placed and maintained at a much higher level than the current practice.
Notably, 3M has developed signs with embedded smart codes that can be read by a vehicle sensor. The information is encoded using special films and inks, which infrared cameras can read. Smart codes can refer the vehicle back to a central database with regularly updated information about the road. Other sign technologies may include Bluetooth beacons or radio frequency identification devices (RFID) to make signage machine-readable. Several recommendations are suggested that can assist local agencies in preparing for CAVs.
- Remove non-standard, blocked, damaged, or faded signing.
- Consistent use, proper maintenance, and replacement of signs
- When available, consider the use of signs with smart codes, which can be read by a vehicle with an infrared (IR) light source at a distance. The codes should include information such as GPS coordinates, sign installation dates, maintenance dates, etc.
- Implement diamond-grade reflective sheeting, which makes the signing readable over a range of angles and during inclement weather.
3. Traffic signals & communication
Along with pavement markings and signing, CAVs will need to detect and identify traffic signals that generate Signal Phase and Timing (SPaT) messages, including green, yellow, red, and the amount of time left until the next phase. Several studies recommend implementing dynamic message system (DMS) signs and new traffic signal controllers that have an internet protocol (IP)-ready ports and National Transportation Communications for Intelligent System Protocol (NTCIP) compliance for full-scale CV deployment and the ability for integration into advanced traffic management systems (ATMS).
The simplest recommendation is to ensure enough space for additional hardware and communications during the replacement of traffic signal controllers. Additionally, agencies will need to work with vendors to determine which communications technologies will be required to allow vehicles to send and receive data in conjunction with signal controllers as technologies evolve. They also need to consider future communication needs as part of roadway plans.
Maintenance is a key aspect of accommodating AVs. It refers to pavement and winter weather maintenance of any roadway. Significant degradations in roadway surface conditions pose a considerable concern for CAVs since it is uncertain how imaging systems may interpret these surface conditions. It can also make it difficult for a CAV to predict the behavior of other road users.
Additionally, the presence of snow and rain obscure pavement markings and signing, making it difficult for camera systems to detect and interpret them. Therefore, it is necessary to maintain roads to a higher standard than for human drivers. At this point, it is unknown the extent to which additional maintenance may be needed to accommodate CAVs. However, the best recommendation is to maintain or implement timely maintenance, mainly when significant surface degradation, such as potholes, occurs.
5. Consistency and standardization
The most existing rules of the road were developed over the last 100 years. They are based on the assumption that drivers are human beings. But things are going to change. Consider this: how does law enforcement pull over a fully autonomous vehicle that has committed a traffic violation? Law enforcement and other agencies, therefore, must refine the legal mechanisms around the driver as the central actor in driving.
Another area where standardization is required is parking. The local governments must investigate policies and programs governing the location, form, price, and parking amount. This includes monitoring how changes in vehicle ownership models and CAV adoption could impact parking revenue, mainly for municipalities that rely heavily on this revenue to support public services. Local governments may also need to develop specifications for parking design for self-driving cars and may need to examine redevelopment opportunities for parking lots in dense urban areas.
6. Data capture and sharing
In the longer term, there is an expectation that CAVs will collect and share data as road and traffic conditions change. For instance, a lead vehicle, encountering congestion, major traffic events, hazard warnings, environmental conditions or road closures can share this information in real-time with other vehicles or corresponding agency, so subsequent vehicles can adjust accordingly. A road database inventory or a high-definition mapping is one of the most fundamental elements and will require highly detailed information such as lane geometry, horizontal and vertical curve characteristics, and speed limits. However, the cost of creating such high-definition maps is challenging. If an agency decides to invest in high-definition mapping, some guidance may be needed to address liability issues.