Would relaxing speed limits aggravate safety? A case study of Hong Kong.

This paper studies the effect of the changed speed limits on accident counts for major roadways in the urban environment of Hong Kong. In 1999-2002, the speed limits of a number of sections of roadway were reviewed and increased. Nineteen of them were major roadways. Their speed limits were raised by 10-20 km/h from 50 to 70 km/h. Before and after studies were carried out to investigate the changes in accident counts with respect to the set of carefully chosen comparison groups. Qualification tests for these comparison groups were conducted to confirm their suitability for the studies. In the majority of the treatment sites, the accident counts were worse after the increase in speed limits, both for the category of fatal, serious and slight (FSS) accidents, and for the category of fatal and serious (FS) accidents. Overall, the relaxation of the speed limit from 50 to 70 km/h increased the FSS accident counts by 15% and the FS accident counts by 1%. The relaxation of the speed limit from 70 to 80 km/h increased the FSS accident counts by 18% and the FS accident counts by 36%.

[1]  Gang-Len Chang,et al.  Intervention analysis for the impacts of the 65 mph speed limit on rural interstate highway fatalities , 1993 .

[2]  Richard E. Allsop.  SOME TRAFFIC SAFETY IMPLICATIONS OF MOVEMENT OF GOODS BY ROAD , 2003 .

[3]  S. Garber,et al.  The effects of the new 65 mile-per-hour speed limit on rural highway fatalities: a state-by-state analysis. , 1990, Accident; analysis and prevention.

[4]  S C Wong,et al.  A qualitative assessment methodology for road safety policy strategies. , 2004, Accident; analysis and prevention.

[5]  Charles Lave,et al.  EFFECT OF THE 65 M.P.H. SPEED LIMIT ON HIGHWAY SAFETY IN THE U.S.A. (WITH COMMENTS AND REPLY TO COMMENTS) , 1992 .

[6]  Chester G. Wilmot,et al.  EFFECT OF SPEED LIMITS ON SPEED AND SAFETY: A REVIEW , 1999 .

[7]  Patrick S. McCarthy,et al.  Effect of speed limits on speed distributions and highway safety: A survey of recent literature , 2001 .

[8]  A. Lund,et al.  THE FATALITY CONSEQUENCES OF THE 65 MPH SPEED LIMITS, 1989 , 1991 .

[9]  Edythe Traylor Crump.  55 : a decade of experience , 1984 .

[10]  S M Rock,et al.  Impact of the 65 mph speed limit on accidents, deaths, and injuries in Illinois. , 1995, Accident; analysis and prevention.

[11]  A K Lund,et al.  Changes in motor vehicle occupant fatalities after repeal of the national maximum speed limit. , 1999, Accident; analysis and prevention.

[12]  Margaret O'Mahony,et al.  DISTANCE AND TIME BASED PRICING IN DUBLIN , 2000 .

[13]  Lawrence J Cook,et al.  Effect of repeal of the national maximum speed limit law on occurrence of crashes, injury crashes, and fatal crashes on Utah highways. , 2004, Accident; analysis and prevention.

[14]  Ezra Hauer,et al.  The harm done by tests of significance. , 2004, Accident; analysis and prevention.

[15]  J W Dunn,et al.  ACCIDENTS, SPEED DEVIATION AND SPEED LIMITS , 1971 .

[16]  C. Lave.  Speeding, Coordination, and the 55 MPH Limit , 1985 .

[17]  pau,et al.  Road safety | Engineering , 2005 .

[18]  Hong Kam Lo,et al.  Road Safety - Strategy and Implementation , 2002 .

[19]  Peter Cummings,et al.  Freeway speed limits and traffic fatalities in Washington State. , 2002, Accident; analysis and prevention.

[20]  Ezra Hauer,et al.  Observational Before-After Studies in Road Safety , 1997 .