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Author, Date | Speed Limit | Average 85th Percentile Speed | ||||||||||||||||||||
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Location | #S | B | A | B | AL | AH | Remarks | |||||||||||||||
Urban | ||||||||||||||||||||||
St. Paul, Minnesota | Avery, 1960 | 7 | 30 | 35 | 35.5 | 35.8 | Compliance increased from 36 to 80 percent. | |||||||||||||||
4 | 30 | 40 | 39.4 | 40.8 | Compliance increased from 19 to 82 percent. | |||||||||||||||||
West Lafayette, Indiana | Elmberg, 1960 | 1 | 35 | 30 | 38.4 | 38.5 | Percentage of vehicles exceeding the speed limit by 5 mi/h or more increased from 10 to 38 percent. | |||||||||||||||
St. Joseph | Ogawa, 1962 | 1 | 30 | 35 | 30.6* | 31.3* | Speed limit revisions based on 85th percentile speeds. The mean speed increase in Orden is statistically significant. | |||||||||||||||
Orden | 1 | 40 | 35 | 32.2* | 33.3* | |||||||||||||||||
Fithian, Illinois | 1 | 35 | 40 | 34.9* | 35.3* | |||||||||||||||||
Columbia, South Carolina | Roberts, 1967 | 1 | 35 | 40 | 42.5 | 41.0 | Compliance increased from 28 to 75 percent | |||||||||||||||
10 California Cities | Spitz, 1984 | 40 | NA | NA | 39.9 | 40.3 | The 85th percentile speed in the 27 comparison samples where no change in the limit was made increased from 40.1 to 40.8 mi/h. | |||||||||||||||
10 | NA | NA | 36.9 | 38.6 | ||||||||||||||||||
3 Urban Fringe Areas in Texas | Dudek, 1986 | 6 | 55 | 45 | 55.9 | 54.0 | Lowering the speed limit had little effect on vehicle speeds and speed variance | |||||||||||||||
Rural | ||||||||||||||||||||||
Illinois | Kessler, 1959 | 30 | 30 | 40 | 38.9 | 38.4 | Driver compliance increased from 39 to 85 percent. | |||||||||||||||
Houston District, Texas | Rowan, 1962 | 1 | 60 | 55 | 55.5 | 55.0 | Speed limits were established in the after periods based on the 85th percentile speeds. A slight increase in the dispersion of speeds was reported after the new limits were established | |||||||||||||||
1 | 60 | 50 | 53.7 | 52.0 | ||||||||||||||||||
1 | 60 | 45 | 47.3 | 46.4 | ||||||||||||||||||
1 | 60 | 40 | 41.5 | 39.9 | ||||||||||||||||||
1 | 60 | 35 | 40.2 | 38.9 | ||||||||||||||||||
1 | 60 | 30 | 31.2 | 33.2 | ||||||||||||||||||
Paris District, Texas | 1 | 60 | 55 | 55.2 | 51.2 | |||||||||||||||||
1 | 60 | 50 | 51.5 | 59.9 | ||||||||||||||||||
1 | 60 | 45 | 47.6 | 43.9 | ||||||||||||||||||
1 | 60 | 40 | 40.4 | 38.6 | ||||||||||||||||||
1 | 30 | 55 | 53.2 | 50.5 | ||||||||||||||||||
1 | 30 | 50 | 52.6 | 51.3 | ||||||||||||||||||
1 | 30 | 45 | 45.4 | 45.2 | ||||||||||||||||||
1 | 30 | 40 | 40.3 | 42.0 | ||||||||||||||||||
1 | 30 | 35 | 36.8 | 38.4 | ||||||||||||||||||
Operational studies | ||||||||||||||||||||||
Massachusetts | Oct. 1966 | 19 2-lane | 30-45 | 20-35 | 47.5 | 48.3 | After posting 10mi/h lower and higher limits than existing zones, no differences in 85th percentile speed were found | |||||||||||||||
30-45 | 40-55 | 48.0 | ||||||||||||||||||||
6 d-lane | 50-55 | 40-45 | 60.7 | 60.3 | ||||||||||||||||||
60-65 | 60.7 | 61.0 | ||||||||||||||||||||
Minnesota | Jan. 1979 | 12 2-lane | 45 | 30 | NA | 43.6 | ||||||||||||||||
4 4-lane | 40 | 30 | 42.0 | 40.3 | ||||||||||||||||||
Washington | 1981-82 | 3 | 25 | 30 | 34.7 | 34.3 | ||||||||||||||||
1 | 50 | 55 | 57.0 | 59.0 | ||||||||||||||||||
1 | 50 | 35 | 43.0 | 42.0 | ||||||||||||||||||
3 | 40 | 35 | 45.0 | 43.7 | ||||||||||||||||||
Michigan | 1982 | 4 | 25 | 35 | 37.6 | 36.0 | Compliance increased from 10 to 81 percent. | |||||||||||||||
4 | 55 | 50 | 56.8 | 54.8 | Compliance decreased from 73 to 56 percent. | |||||||||||||||||
4 | 55 | 50 | 57.8 | 56.0 | Compliance decreased from 71 to 46 percent. | |||||||||||||||||
5 | 45 | 35 | 49.2 | 47.0 | Compliance decreased from 56 to 7 percent. |
NA | = | Not Available |
* | = | Denotes mean speeds, not 85th percentile speeds |