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Road Management & Engineering Journal
Copyright © 1997 by TranSafety, Inc.
March 1, 1997
TranSafety, Inc.
(360) 683-6276
Fax: (360) 335-6402
transafety@live.com

Addressing Human Factors and Injury Accidents Through the Safety Management System
Winter Maintenance Technology Practices -- Learning from Abroad
Township Must Erect and Maintain Stop Signs Where Township Road Intersects State Road
Inventorying Highway Signs
Call Boxes in Freeway Medians?


















Call Boxes in Freeway Medians?

Should Emergency Call Boxes Be Placed in Freeway Medians? queried the title of a paper delivered at the 74th Annual Meeting of the Transportation Research Board (January 1995) by James H. Banks of San Diego State University s Civil Engineering Department. In most cases probably not, concluded Banks. They are handy and cost efficient, but the possible hazard they pose over right-shoulder-mounted telephones, together with broad official opposition, would seem to discourage their installation. The report suggested median-mounted call boxes might be a good idea, however, where access to the far-right shoulder of the freeway is blocked, where there is no adequate right shoulder, or where the freeway has reversible lanes.

Opinion Survey. Highway administrators and patrol officers surveyed in 1993 for this study opposed median telephones by a 60-to-40 margin, on the grounds that median-mounted telephones would lead more drivers to park on the left shoulder. Parking on the left shoulder was assumed to be more dangerous than parking on the right shoulder because of higher speeds in the fast lane. Lone exceptions to the opposition to median-mounted emergency call boxes were consultants and telephone people who sell and service emergency telephones on California s freeway system; they unanimously supported median call boxes.

Crash Figures. A 1991-1992 survey of 602 Southern California crashes involving dismounted drivers (drivers who had gotten out of their vehicles) found only two cases were definitely related to the use of emergency call boxes. Only one dismounted driver was crossing the freeway to use a telephone. Banks concluded, A review of accident reports to determine the number of persons struck while attempting to cross freeway lanes to access call boxes revealed that such accidents are exceedingly rare.
Of the 602 dismounted-driver crashes studied, 8 to 10 percent occurred on the left shoulder, compared with 25 to 35 percent on the right shoulder. Correcting for relative exposure, researchers calculated the risk of a dismounted driver being hit on the left shoulder was 3 or 4 times greater than the risk of being hit on the right shoulder.

Cost. The cost of installing and maintaining solar-operated median call boxes at .4-kilometer (quarter-mile) intervals would be around $3,500 per year per kilometer (.62 miles). The author compared this with an estimated $110,000 per kilometer (.62 miles) per year to provide 24-hour freeway patrol service (FPS). Current 8-hour-per-day FPS costs around $25,000 per kilometer-year (.62-mile- year). It is not certain, however, that median call boxes would reduce the need for FPS on high-traffic urban freeways.

Conclusions. Banks recommended median call boxes only for high- occupancy-vehicle (HOV) lanes separated from the right lanes and shoulder of the freeway by a barrier and only where wide shoulders with no sight obstructions exist.

California had 14,500 emergency call boxes in operation as of June 1994, but the only ones mounted in the median were for reversible-lane freeways. The increased popularity of in-vehicle cellular telephones may eventually reduce the need for an expanded emergency call box system.

Copyright © 1997 by TranSafety, Inc.


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