- 2070 Chaitra (old course) · 6 marks
On-street vs off-street parking; kerb parking geometry
Short answer
On-street parking is cheap, convenient but reduces road capacity and safety; off-street is expensive, secure, high capacity, no traffic impact. Parallel parking uses ~5.5–6.0 m kerb per car, least width; angle parking (30°,45°,60°,90°) reduces kerb length per car but needs wider bay and aisle.
Compare on-street and off-street parking. Draw neat sketches showing parallel and angle kerb (on-street) parking geometry.
Comparison of on-street and off-street parking
| Aspect | On-street | Off-street |
|---|---|---|
| Location | On the carriageway edge | In lots, garages, basements |
| Cost | Very low (markings, signs, meters) | High (land, construction, staff) |
| Convenience | Very close to the destination | Slightly further to walk |
| Effect on traffic | Reduces road capacity and safety | No effect on road capacity |
| Capacity | Small | Large, especially multi-level |
| Safety and security | Lower; risk of theft/damage | Better supervision and security |
| Control | Hard; often illegal parking | Easy; gates, tickets, fees |
| Pedestrian effect | Obstructs footpath | Protects footpath |
Parallel parking geometry
Bay size for a car: about 5.0 m long x 2.5 m wide, and with the gap needed to manoeuvre in and out each car uses about 5.5-6.0 m of kerb (trucks need about 7.5 m x 3.75 m, buses more). The car is parked parallel to the kerb, which needs the least road width but gives the fewest bays.
carriageway
--------------------------------------
<- traffic ->
======================================== kerb line
_____5.0 m_____ _____5.0 m_____
| car | gap | car | 2.0-2.5 m
|_________| |_________|
======================================== kerb
Angle parking geometry (30, 45, 60, 90 degrees)
The vehicle is parked at an angle to the kerb, front end first (or reversed in). A larger angle gives more cars per length of kerb but needs a wider strip of road and a wider aisle.
45 degree parking
carriageway <- traffic ->
======================================
\ \ \ \ \ \ stall width along kerb
\__\__\__\__\__\ = 2.5 / sin(angle)
====================================== kerb
| Angle to kerb | Kerb length per car | Depth of the bay from kerb |
|---|---|---|
| 0 (parallel) | 5.5-6.0 m | 2.0-2.5 m |
| 30 degrees | about 5.0 m | about 4.7 m |
| 45 degrees | about 3.5 m | about 5.3 m |
| 60 degrees | about 2.9 m | about 5.6 m |
| 90 degrees | about 2.5 m | about 5.0 m |
(For a car 2.5 m wide x 5.0 m long: kerb length per car = 2.5/sin(angle); bay depth = 5.0 sin(angle) + 2.5 cos(angle).) The aisle width kept for manoeuvring is largest for 90-degree parking (about 6 m).
✓ Answer checked by Claude Opus 5.5 (high effort)
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