The mobility and efficiency of California highways are impeded by the recurrent and non-recurrent congestion on a daily basis. Roadway incidents, especially collisions, often result in traffic congestion and travel delays. This project is initiated to explore the use of technologies that will potentially bring direct and immediate benefits to the law enforcement officers and other personnel who are involved in the handling of collision sites and subsequent investigations. The work carried out in this project includes three major components: (1) The experimentation of integrated vehicular technology systems to provide assistance for law enforcement officers, (2) The exploration of utilizing GPS devices for vehicle and incident locations, and (3) The development of photogrammetry tool to extract supplementary information from collision scenes.

Valuable insights were gained through collaborations with the University of New Hampshire Project 54 and the City of Carlsbad, California, Public Safety Technology Programs. The key factors to successful deployment of technological systems are the easy-to-learn operation features and friendliness of user-machine interface. Integrated multiple-function capabilities and open architecture are important considerations in adopting technological systems to ensure favorable cost-benefit returns of investments from the perspectives of local jurisdictions or agencies.

This report constitutes the first phase of the project, sponsored under California PATH Task Order 5216, while the complete report is documented in a joint report for Task Order 6216.

The mobility and efficiency of California highways are impeded by the recurrent and non-recurrent congestion on a daily basis. Roadway incidents, especially collisions, often result in traffic congestion and travel delays. This project is initiated to explore the use of technologies that will potentially bring direct and immediate benefits to the law enforcement officers and other personnel who are involved in the handling of collision sites and subsequent investigations. The work carried out in this project includes three major components: (1) The experimentation of integrated vehicular technology systems to provide assistance for law enforcement officers, (2) The exploration of utilizing GPS devices for vehicle and incident locations, and (3) The development of photogrammetry tool to extract supplementary information from collision scenes.

Valuable insights were gained through collaborations with the University of New Hampshire Project 54 and the City of Carlsbad, California, Public Safety Technology Programs. The key factors to successful deployment of technological systems are the easy-to-learn operation features and friendliness of user-machine interface. Integrated multiple-function capabilities and open architecture are important considerations in adopting technological systems to ensure favorable cost-benefit returns of investments from the perspectives of local jurisdictions or agencies.

This paper studies the design of ad-hoc Medium Access Control (MAC) protocols for a vehicle or the roadside to send safety messages to other vehicles. Such a protocol is needed by Advanced Vehicle Safety Systems (AVSS) and the national Dedicated Short Range Communications (DSRC) architecture. The problem is formulated to meet the communication requirements of vehicle safety applications and the DSRC multi-channel operation model. We propose several ah-hoc protocols, all based on the principles of repetition coding. Analytical bounds of the protocols' performance are derived. Simulations are conducted to compare the performance of the protocols in terms of probability of reception success and channel busy time. The best among the proposed protocols is shown to significantly outperform IEEE 802.11 MAC protocol in vehicle safety communication environment. We obtain the optimal relation between the performance and protocol design, in particular that of data rate and transmission power. The sensitivity of the protocol performance is tested under various communication conditions as well as vehicle traffic conditions. Feasible combinations of the communication and highway traffic parameters are found to meet specific performance requirements on communication.