This study documents the operational experience of the I-94 Lowry Hill Tunnel Traffic Management System situated in Minneapolis, Minnesota. This system is comprised of a computerized vehicle detection system, a status display map, a closed circuit television system, changeable message signs, and lane control signals.
Results of the study indicate that drivers do respond to information conveyed via lane control signals by shifting from incident to non-incident lanes. The effectiveness of the changeable message sign was, however, not adequately documented in this study. In the opinion of the traffic management system operations personnel, the CCTV is an indispensable tool for immediate detection of the incident, quick response to emergencies, and for having credibility with State Patrol forces.
This study is concerned with the noise field near and surrounding a highway tunnel. The results of the field survey indicate that the sound pressure level, at the front of a tunnel, drops off rapidly as the distance away from the portal increases. The same results (but of a lower magnitude) occur when the measurements were taken on top of the tunnel.
