Citation

Fitzpatrick K, Balke K. Transp. Res. Rec. 1995; 1500: 146-152.

Copyright

(Copyright © 1995, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Three types of medians are typically used on four-lane rural highways in Texas: raised (or depressed) medians; two-way, left-turn lanes (TWLTLs); and flush medians. On roads with flush medians, the area between the travel lanes is paved and can easily be traversed by a vehicle. This type of median is typically used in areas that shift from rural to suburban. Research was conducted to examine the differences in the operation and safety of four-lane rural highways with TWLTLs and four-lane rural highways with flush medians. A review of accident rates found no statistical differences in the number of accidents on highways with TWLTLs and highways with flush medians when driveway densities were low. Field studies also found no difference in the way these two median treatments operate in rural areas. Therefore, it was concluded that drivers use flush medians and TWLTLs similarly. However, Texas law prohibits the use of flush medians as a storage area or an acceleration/deceleration area for turning left into and out of adjacent properties. The results of the research suggest that drivers ignore the meaning of the solid yellow lines used to mark flush medians. Therefore, to promote uniformity and consistency, it is recommended that flush medians be used only on highways on which the frequency and spacing of the driveways permit individual median openings at each driveway. On four-lane rural highways on which this is not possible, it is recommended that TWLTLs be used.

Language: en

Keywords

Accident prevention; Highway accidents; Laws and legislation; Rural areas; Speed; Statistics; Pavements; Highway engineering; Collision avoidance; Ground vehicles; Highway markings; Median dividers