Answer: The access route does not have to be in front of
parked vehicles. However, both the 1994/1990 ADA Accessibility Guidelines
(ADAAG; see Figure 9) and the 502.3 Advisory of the 2010 ADA Standards state that the
preferred location for the pedestrian access route is in front of the parked
vehicles.
How I wish parking lot designs would keep the accessible pedestrian route in
front of the vehicles! People in wheelchairs, children, and little people
typically cannot be seen from the rear window. Every time I have to pass behind
parked vehicles I say a quick prayer that someone doesn’t suddenly pull out of
their space and hit me. With SUVs and trucks, it’s even worse. To demonstrate
the dangers, I’ve seen many a news station gather together a group of children
behind an SUV — none could be seen from the vehicle’s rear window.
Figure 9 in the 1990/1994 ADAAG regulations shows the access route across
the front of the parking spaces.

The pedestrian access route is located in front of the parked vehicle.
Photos: Michele Ohmes
Other ADA guidelines and standards for access routes
include:
When dealing with narrow sidewalks
The following photo and graphics show examples of narrow sidewalks with
parallel curb ramps versus one with a perpendicular curb ramp (i.e., with flared
sides). The photo shows how the simple parallel ramp solution flows easily —
eliminating the warping problem that comes with flared-sided ramps — for the
wheelchair user trying to turn left or right on the sidewalk. The graphics are
from the Federal Highway Administration (FHWA) manuals Designing Sidewalks and
Trails for Access (Part I and Part II).
Parallel curb ramps with gentle slopes are easy for wheelchair users to
navigate.

A curb ramp with flared sides may be difficult for wheelchair users to
traverse if it does not have a level landing behind the ramp. This is a major
problem that I see often on narrow sidewalks.
On narrow sidewalks, perpendicular curb ramps often do not have enough
landing space — a level area of sidewalk at the top of a curb ramp facing the
ramp path. Thus, wheelchair users cannot avoid the changing grade or cross slope
of the ramp while turning or crossing through (see graphic above). This can
cause stability or tipping issues with the wheelchair.
The parallel ramp works for both public sidewalks and for exiting from a
facility’s access aisle to narrow sidewalks. Although the FWHA manuals point out
that with the parallel curb ramp people are forced to navigate two ramps, if the
ramps have a gentle slope the problem becomes minimal versus the warped
situation of flared sides with no landing space for the wheelchair user —
especially the manual wheelchair user.
Navigating islands in parking areas
Another issue is the presence of islands at parking locations. If the island
has a sidewalk with curbs, a wheelchair user cannot take advantage of the
shortest route (see image below). The solution: cut-through or curb ramps at
islands (see examples in below graphic).

This island has a sidewalk with curbs, which prevents a wheelchair user
from using the shortest route from the parking area to the facility/access
route.
At left is a cut-through island and at right is a ramped island. Both are
ideal solutions to keep islands in parking areas accessible. Source: 2010 ADA
Standards, Figure 406.7.
The following are best practices to consider for access from parking
locations:
1. Place the path in front of vehicles versus behind
2. The continuous
path should be on the shortest route possible
3. Place the entrance curb
ramps closest to the actual entrance, instead of down the walkway from the
entrance
4. Where a sidewalk on an island exists from the parking location,
be sure to have it ramped or designed with a complete cut-through.
This is just the tip of the process, but I hope it gets you thinking about
the importance of putting yourself in the situation as an end-user and then
thinking through the design process.