California Partners for Advanced Transportation Technology

A new architecture for a mobile ad-hoc communication network is developed, and simulation results show that the proposed MAC protocol can enhance transmission success probability from 0 to 97%. Two novel applications of vehicle-to-vehicle networks are then developed and simulated. The first application is a \Cooperative Adaptive Cruise Con- trol" which uses communicated information to improve on ordinary cruise control systems. Communicating a \virtual brake light" between vehicles is shown to decrease the accelerations required to maintain safe following distances in cut-in and hard braking situations. The second application is a \Cooperative Estimation" algorithm. The idea behind this algorithm is that each vehicle on the road is potentially a driving condition \sensor." By combining data communicated from many vehicles on the roadway, the cooperative estimation algorithm is able to produce estimates of driving time and road condition that are significantly better than those that any one vehicle could produce on its own. While developing the cooperative road condition estimation algorithm, it is found that the problem's crux is at the vehicle level, so the friction estimation problem is then investigated at a vehicle/tire level through exten- sive experimentation. An exciting new type of \slip-based" road condition estimator is developed and experimentally shown to be able to distinguish between wet and dry roads using no dedicated road condition sensors sen- sors. In-depth literature review complements our own results and shows that \slip-based" estimators of the type developed may be very useful to help solve the AHS road condition estimation problem.