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原文传递 TECHNICAL PERFORMANCE OF DIRECT'S TRAVELER INFORMATION SYSTEMS.

题名：	TECHNICAL PERFORMANCE OF DIRECT'S TRAVELER INFORMATION SYSTEMS.
作者：	Ristenbatt-Marlin; Shahine-Ghassan-E
关键词：	DIRECT-Program-:-Michigan; Radio-Data-Systems-Traffic-Message-Channel; advanced-driver-information-systems; highway-advisory-radio
摘要：	The Driver Information using Experimental Communication Techniques (DIRECT) Operational Field Test aims to increase the number of drivers who are aware of traffic incidents on their route by offering affordable route-specific automatic alerting. Both broadcast and roadside localcast delivery methods were tested on a 15-mile segment of I-75 in the Detroit area. Recruited drivers who used the segment on their commute route drove vehicles equipped with one of the delivery methods. Traffic information was provided by a professional announcer located at the Michigan Intelligent Transportation Systems Center (MITSC). The broadcast method used the Radio Data System (RDS) digital subcarrier of WDTR's FM signal to control the RDS entertainment radio; the analog traffic information was on another subcarrier. Four roadside localcast transmitter sites in the segment implemented a localized Low Power HAR and an Automatic HAR. While all three radio methods proved capable of providing clear, understandable messages the perceived quality was highest for the FM subcarrier technique. However, the subcarrier messages did suffer unobjectionable multipath "pops" in the downtown area. The control reliability, for automatic interrupt, was the greatest for the RDS subcarrier. The AHAR control reliability was poor, missing interrupts about 25% of the time; the "alerting" for LPHAR used flashing lights,which operated poorly due to use of batteries for power. The broadcast technique was considerably less costly than either of the roadside techniques. In considering metro-wide deployment it is concluded that limited-distance segmented coverage, as in LPHAR and AHAR offers an advantage only if diversion information is included. With no diversion information all drivers approaching an incident should receive the same message; hence a wide-area broadcast approach is as effective as a segmented one. However, a normal power HAR deployment with flashing signs also remains a candidate. We believe the most cost-beneficial improvement over current all-incident spaced traffic reports on AM or FM stations would be a route specific service based on using the RDS subcarrier (only) of the FM stations along with in-vehicle paper maps.
总页数：	ITS America. Meeting (8th : 1998 : Detroit, Mich.). Transportation technology for tomorrow : conference proceedings. 1998. pp12
报告类型：	科技报告