A lot of you are asking questions about ramp grades, so let's clear the air.
Here are some of our most frequently asked questions about how to design an on-site vehicle ramp.
Many elements guide ramp design and set controls for ramp configurations. While each site is different and requires a unique design, you can count on these frequently asked questions as a general guide for almost all ramp design requirements.
So with that out of the way, it's time to answer some of the most common questions we get about ramps.
Why does the ramp have to be a maximum of 1:10 (10%) near the property boundary?
The grade of ramps is limited within 5m of the property boundary to maximise pedestrian's line-of-sight and allow for comfortable vehicle operation as drivers cross the footpath. The 1:10 grade is also essential to avoid vehicle scraping issues at the property boundary, where nature strips and footpath grading tend to be.
What determines the maximum grade of a ramp?
Typically, ramps can have a maximum grade of 1:5 (20%) to 1:4 (25%). The maximum grade allowed for car parks open to the public is typically 1:5 (20%). On the other hand, private car parks for residents or staff can be steeper at up to 1:4 (25%).
What are transitions, and why do I need them?
If a ramp were to change directly from a flat section to the maximum grade (20-25%), the car's underside would scrape or snag on the ramp. For this reason, traffic engineers use transitions. Transitions allow for a more gradual change in grade between the main ramp and the flatter sections at the top and bottom.
How long should a transition be?
Typically, transitions need to be a maximum of 2m long to be effective.
How do I figure out the ramp grade on a curve or bend?
Sometimes ramps include a curve or bend, which results in different ramp lengths along either side of the accessway. As the length of the ramp is shortest on the side, the inside of the bend or curve will govern the design. The length is always longer on the outside of a curved ramp, and ramp grades are typically flatter and less critical.
What happens if I have an unusual site with significant constraints?
For challenging sites, it is always best to seek traffic engineering advice early. Traffic engineers can undertake detailed individual assessments, including custom ground clearance simulation, to ensure your ramp doesn't result in scraping.
Have another question about ramp grades? Feel free to reach out, and let's work together to demystify your ramp design.