Roadside improvement /

Cover title.

Improved roadside turnouts for limited access highways.

Mode of access: Internet.

Roadside improvements for local roads and streets /

"HHI-23/10-86(4M500)QE"- P. [4] of cover.

The roadsides of Oregon; a survey.

Report of a study of the problem of roadside improvement along the highways of that state.

Federal highway beautification assistance act of 1979 [microform] : hearings before the Subcommittee on Transportation of the Committee on Environment and Public Works, United States Senate, Ninety-sixth Congress, first session, on S. 344 ... July 17 and 18, 1979.

Reuse of record except for individual research requires license from Congressional Information Service, Inc.

Assessment of non-traditional controls on ambient air quality /

"Project no. 10.090."

Illinois Transportation Enhancement Program : Cycle III /

"October 1994."

Report of the Illinois Mississippi Scenic Parkway Commission to His Excellency Otto Kerner and the Seventy-Fifth General Assembly.

"January 12, 1967"--Cover letter.

Tree propagation along Illinois highways : report to the Illinois General Assembly.

Cover title.

Illinois Transportation Enhancement Program /

"ITEP is a three year program. Projects funded through the Illinois Transportation Enhancement Program include: scenic/historic highways; historic transportation structure rehabilitation; pedestrian and bicycle facilities; landscaping; transportation museums; outdoor advertising control."

Highway beautification program digest.

Mode of access: Internet.

Junkyards, the highway and visual quality : final report /

Mode of access: Internet.

A simulation study of unified GPS and roadside ranging technologies for vehicle positioning

The future vehicle navigation for safety applications requires seamless positioning at the accuracy of sub-meter or better. However, standalone Global Positioning System (GPS) or Differential GPS (DGPS) suffer from solution outages while being used in restricted areas such as high-rise urban areas and tunnels due to the blockages of satellite signals. Smoothed DGPS can provide sub-meter positioning accuracy, but not the seamless requirement. A disadvantage of the traditional navigation aids such as Dead Reckoning and Inertial Measurement Unit onboard vehicles are either not accurate enough due to error accumulation or too expensive to be acceptable by the mass market vehicle users. One of the alternative technologies is to use the wireless infrastructure installed in roadside to locate vehicles in regions where the Global Navigation Satellite Systems (GNSS) signals are not available (for example: inside tunnels, urban canyons and large indoor car parks). The examples of roadside infrastructure which can be potentially used for positioning purposes could include Wireless Local Area Network (WLAN)/Wireless Personal Area Network (WPAN) based positioning systems, Ultra-wide band (UWB) based positioning systems, Dedicated Short Range Communication (DSRC) devices, Locata’s positioning technology, and accurate road surface height information over selected road segments such as tunnels. This research reviews and compares the possible wireless technologies that could possibly be installed along roadside for positioning purposes. Models and algorithms of integrating different positioning technologies are also presented. Various simulation schemes are designed to examine the performance benefits of united GNSS and roadside infrastructure for vehicle positioning. The results from these experimental studies have shown a number of useful findings. It is clear that in the open road environment where sufficient satellite signals can be obtained, the roadside wireless measurements contribute very little to the improvement of positioning accuracy at the sub-meter level, especially in the dual constellation cases. In the restricted outdoor environments where only a few GPS satellites, such as those with 45 elevations, can be received, the roadside distance measurements can help improve both positioning accuracy and availability to the sub-meter level. When the vehicle is travelling in tunnels with known heights of tunnel surfaces and roadside distance measurements, the sub-meter horizontal positioning accuracy is also achievable. Overall, simulation results have demonstrated that roadside infrastructure indeed has the potential to provide sub-meter vehicle position solutions for certain road safety applications if the properly deployed roadside measurements are obtainable.