by Bruce Nelligan, Transportation Engineer (EIT), Hamilton Associates
Recently, the Society of Automated Engineers (SAE) held a conference in San Diego on the Future of Transportation Technology. During the conference, delegates were given the opportunity to travel on an Automatic Highway System (AHS). The AHS is located next to the HOV lanes on I-15 in San Diego and is about eight miles in length. Details of the AHS are provided below as quoted from a publication entitled "What is an Automated Highway System?", produced by the National Automated Highway System Consortium.
Definition
An automated highway system (AHS) is a specially equipped roadway on which vehicles can be operated automatically. These vehicles would be fully capable of operating under driver control on all roads and would be able to use many of the AHS features to improve safety on those roads. AHS will evolve from technologies and features that are expected to become available on vehicles and highways in the US over the next 15 years.
Drivers who choose to use the AHS would steer their specially equipped vehicle onto designated lanes of the highway, then release control of the vehicle to the system. The transfer of control may be similar to the way the "cruise control" feature on today's vehicles assumes control of the vehicle's speed. Command of the vehicle's throttle and brakes would ensure a safe distance from the vehicle in front and operation of the vehicle's steering would ensure that the vehicle remains safely in its lane. When the vehicle reaches the exit selected by the driver, it would be steered into a transition area where the driver would resume manual driving.
Justification
It is increasingly difficult for our vehicle-highway system to meet the growing travel demands and serve the increasing transportation needs of the public and commerce. This is reflected in motor vehicle accident statistics and in the increasing daily congestion on urban highways. In 1992, congestion cost the nation (USA) over $100 billion annually while crashes cost in excess of $150 billion annually. Congestion, and its associated costs, are predicted to continue increasing into the foreseeable future. As congestion increases, so do drivers' stress levels. In addition, highway safety continues to be a major concern as more and more drivers use the highways with varying skill and attention levels.
Research indicates that AHS can significantly increase safety, reduce congestion, reduce stress and ensure shorter, more predictable travel times: often using the existing roadway right-of-ways. At the same time, smoother traffic flow with AHS promises to reduce fuel consumption and exhaust emissions.
Safety Benefits
Driver error contributes to over 90 percent of all vehicle accidents. Automated vehicles, cooperating with the highway infrastructure, could eliminate many of these. A design goal of the AHS is to eliminate accidents during normal operation and to manage any faults to safeguard against system failure.
Congestion Reduction
An AHS would reduce congestion by making more effective use of today's highway infrastructure. An automated lane could accommodate two to three times the number of vehicles on a manual lane, even in adverse weather. This is possible because AHS technology can:
This increased capacity can serve as a tool for traffic engineers to improve our surface transportation system to meet the future's increasing travel demand while reducing its impact on the environment.
The technology requires specially equipped lanes and vehicles to function. The technology consists of magnets embedded in the pavement at four foot intervals which guide the vehicle. The cost of constructing an automatic highway system with the magnets is estimated to be approximately $10,000 per mile which is minimal considering the technology has the potential to increase the roadway's capacity to approximately 5,500 vehicles per hour per lane.
Another system based totally within the vehicle was also showcased at the conference. This system uses a video camera mounted on the vehicle's windshield in conjunction with a PC located within the vehicle. The images read by the camera are processed by a software program to detect the location of the lane markings. The vehicle is then automatically steered along the centre of the two lane lines. The hardware necessary is relatively inexpensive but the software costs approximately $30,000. Therefore, it may be a while before this type of technology is market-ready.
The demonstration of the video-based system was quite impressive. The driver would simply activate the turn signal and the vehicle would automatically change lanes in that direction when it was safe to do so. Another demonstration involved a stationary obstacle on the roadway and the vehicle automatically changing lanes to avoid a collision. One question raised during the demonstration was related to the operation of the system in snowy conditions. The response from the technologist indicated that the system cannot be used in this type of weather. However, the system can detect track marks from previous vehicles that have driven along the roadway.
From the presentations attended, the general consensus from individuals involved in the program was that a fully automated highway system would not be introduced overnight. Instead, it is predicted that a series of smaller impact technologies would be introduced to the market that would increase the general public's acceptance of automated travel. These technologies may include:
Some of these technologies are already road-ready or near ready and will likely be introduced to the market in the near future.
Despite the new technologies available to the public, there will always be individuals who refuse to "give up" the wheel and trust the car. These individuals are either driver enthusiasts or simply not willing to accept the technology. Given the fact that many drivers today refuse to use cruise control or automatic transmissions, it is expected that future drivers will always be given the choice between automated and manual driving.
Another issue related to the new technology was whether the emphasis should be on orderly flow, or rapid efficient transportation. Environmentalists worry that high-speed automated roads would be detrimental to the environment by creating more pollution and using more fuel. They prefer modest speed limits, arguing that motorists should be happy with a smooth, safe trip. Auto industry representatives argue that high-speed transit will be a stronger selling point that could win more support faster for automated roads. These issues and others need to be addressed before the technology can be introduced more widely.
Overall, the demonstration was considered to be a success in showcasing Automatic Highway System technologies. These systems have the potential to reduce congestion and increase the level of safety on Canada's highways.
In the meantime, more information about the National Automated Highway System Consortium can be obtained by visiting their website at: http://nahsc.volpe.dot.gov/