Portland study shows addition of bicycle lanes reduces traffic speeds
After adding bicycle lanes to 12 roadways the Portland, OR Office of Transportation concluded that in all cases motor vehicle speeds decreased or stayed the same. The chart below illustrates that the percentages of vehicles traveling at higher speeds shifted towards lower speeds after bicycle lanes were added to the roadway.
Before and After photos of Glisan Street demonstrate how a perceived narrowing of the roadway reduced traffic speeds.
Summary Table: Impact of Bicycle Lanes on Traffic Speeds
|
Location |
Pre-existing Conditions & Project Alterations |
Auto Speed Profile |
|
SE Bybee east of 21st , both directions |
Ш 36' wide residential, 2 lanes and lightly used parking, 14,000 adt. Ш removed parking north side, add bike lanes (7'-4Ѕ’-10'-10'-4Ѕ’) |
decrease: 32-40 mph: 60% to 40%; 41+ mph: 4.6% to 1.3% |
|
SE Woodstock east of 36th, both directions |
Ш 40' wide residential, 2 lanes and moderately used parking both sides, steep grade to east, 10,000 adt. Ш shifted centerline to accommodate uphill bike lane only (18’-10'-4Ѕ’-7Ѕ’) |
no change; some slight decrease in eastbound direction |
|
SE Woodstock east of 60th , westbound[1] |
Ш 50' wide residential, 2 lanes and lightly used parking, 12,000 adt. Ш narrowed travel lanes and added bike lanes (8'-5’-12'-12'-5’-8') |
decrease: 36-44 mph: 58% to 48%; 45+ mph: 3.3% to 1.9% |
|
SE Duke e. of 64th , wbnd., and e. of 65th , ebnd. |
Ш 44' wide residential, 2 lanes and lightly used parking, bus line, 5,000 adt. Ш narrowed travel lanes and parking area, add bike lanes (7Ѕ'-4Ѕ’-10'-10'-4Ѕ’-7Ѕ') |
no change: 33-41 mph: 63% to 64%; 42+ mph: 5.1% to 4.3% |
|
SE 41st s. of Harold, both directions
|
Ш 50' wide residential, 2 lanes and lightly used parking, 3,000 adt. Ш narrowed travel lanes, added bike lanes (8''-5'’-12'-12'-5’-8'') |
no change: 32-40 mph: 51% to 53%; some decrease 41+ mph: 8.2% to 6.5% |
|
NE Glisan e. of 43rd , both directions |
Ш 48' wide residential, 2 lanes and parking, bus line, 10,000 adt. Ш narrowed travel lanes and parking area, add bike lanes (8'-5’-11'-11'-5’-8') |
decrease: 33-41 mph: 57% to 46%; 42+ mph: 3.8% to 1.3% |
|
NE Glisan e. of 30th , both directions |
Ш 56' wide higher density residential, some commercial, 4 lanes and heavily used parking, bus line, 8,000 adt. Ш changed from 4 lanes to 3 (one each direction and center turn lane), added bike lanes (7Ѕ'-5’-10'-11'-10'-5’-7Ѕ') |
decrease: 33-41 mph: 49% to 40%; 42+ mph: 4.7% to 2.6% |
|
N Smith w. of Buchanan, both directions |
Ш 50' wide residential, 2 lanes and lightly used parking, 3,000 adt. Ш narrowed travel lanes, added bike lanes (8'-5'-12'-12'-5'-8'). Traffic calming devices later added. |
decrease: 35-43 mph: 49% to 43%; 44+ mph: 5.6% to 3.5% |
|
NE Multnomah e. of 19th, both directions |
Ш 43' wide residential, 2 lanes and parking (pro-time eastbound 4-6 PM), bus line, 8,000 adt. Ш converted pro-time lane eastbound to 24-hour parking, add bike lanes (7'-4Ѕ’-10'-10'-4Ѕ’-7') |
decrease: 20-25 mph: 19% to 37%; 29-37 mph: 48% to 25%
|
44' Roadway width: 7.5' parking, 4.5' bike lane,
10' motor vehicle lanes
Bike lanes and planters reduce perceived
and actual roadway width.