Accessibility in the built environment is more than a compliance checkbox; it is about creating spaces that serve everyone. Since the passage of the Americans with Disabilities Act (ADA), engineers and designers have been tasked with ensuring that parking lots, sidewalks, pedestrian ramps, and building access points are functional for people of all abilities. For engineers, ADA design is at the heart of planning safe, efficient, and welcoming infrastructure.
At its core, accessibility benefits more than just those with mobility challenges, it helps parents pushing strollers, delivery staff moving equipment, and older adults navigating daily routines. Thoughtful design builds communities that are inclusive, safe, and future-ready.
Accessible Parking Lot Design
Parking lots are often the first point of contact with a building, which makes ADA-compliant parking design a critical priority.
- Number and Type of Spaces: ADA guidelines specify the required number of accessible spaces based on total capacity. At least one in every six must be van accessible.
- Location and Access: Spaces must be located on the shortest accessible route to the building entrance. This route should not pass behind other parked vehicles.
- Dimensions and Surfaces: Standard accessible spaces require an 8-foot width with an adjacent 5-foot access aisle, while van spaces require an 11-foot width with a 5-foot aisle. Surfaces must be smooth, firm, and slip resistant.
- Drainage Considerations: Proper grading prevents water from pooling in accessible spaces or routes, ensuring safety in all weather conditions.
A well-designed parking lot makes accessibility intuitive, not an afterthought.
Sidewalks and Pathways
Sidewalks and pathways guide users through a site, and their design plays a direct role in accessibility.
- Width and Clearance: Sidewalks must have a minimum clear width of 36 inches, though wider walkways are encouraged in high-traffic areas.
- Slopes and Cross Slopes: The running slope of a sidewalk should not exceed 5%, while cross slopes must remain under 2% to prevent wheelchairs from drifting.
- Surface Materials: ADA requires stable, firm, and slip-resistant surfaces. Materials like concrete or asphalt are common, but the key is long-term durability.
- Detectable Warnings: Tactile paving at intersections and transition points helps visually impaired users identify hazards.
Incorporating these details ensures that sidewalks serve as safe and seamless connections between parking areas, ramps, and building entrances.
Pedestrian Ramps and Curb Cuts
Pedestrian ramps and curb cuts are essential for bridging elevation changes. Poorly designed ramps can be dangerous, while well-executed ramps promote safety and independence.
- Slope Requirements: The maximum slope for an ADA ramp is 1:12, meaning one inch of rise for every 12 inches of run. Landings are required at the top and bottom.
- Width and Landings: Ramps must be at least 36 inches wide, with flat landings large enough for wheelchairs to maneuver.
- Alignment and Safety: Ramps should align directly with crosswalks to minimize travel distance in the roadway. Detectable warning strips alert visually impaired pedestrians of the transition.
- Integration with Existing Conditions: When retrofitting older sites, engineers must creatively work around space constraints, grading, and drainage without compromising compliance.
Attention to these details turns ramps from barriers into gateways.
Building Access and Entryways
An accessible path should continue seamlessly from the parking lot and sidewalks to the building’s main entrance.
- Clear Routes: Entrances should connect to the accessible route without steps or abrupt level changes.
- Landings and Slopes: Door landings must be level, and approaches must meet ADA slope requirements.
- Thresholds and Doors: Thresholds should be no more than half an inch high, and doorways should have a minimum clear opening of 32 inches. Automatic doors or lever-style handles further improve usability.
- Maintenance Matters: Snow, ice, or debris blocking access routes is just as problematic as a design flaw. Regular maintenance is part of ensuring accessibility.
When the route to the building is thoughtfully designed, all users can approach and enter with dignity and ease.
Common Challenges in Accessibility Projects
Despite clear ADA guidelines, site/civil engineers often face challenges when implementing accessible designs:
- Space Limitations: Older properties may not have room for compliant ramps or expanded parking stalls.
- Topography and Drainage: Sloped sites make compliance more complex, requiring innovative grading solutions.
- Coordination Across Disciplines: Accessibility involves collaboration between architects, engineers, and contractors to ensure a cohesive outcome.
By addressing these challenges early in design, costly retrofits and compliance issues can be avoided.
View Some MFS ADA Projects
Beach 24th and 25th Street ADA Ramps
Medgar Evers College- Caroll Building Renovations ADA Bathroom & Athletic Center
NYCDDC - DeGraw Firehouse Renovation
Beyond Compliance: The Value of Universal Design
While ADA sets the minimum standards, many firms are embracing universal design principles, which create spaces usable by the widest range of people without adaptation. For example:
- Wider sidewalks serve both wheelchair users and parents with double strollers.
- Gentle slopes benefit those with mobility aids and cyclists.
- Clear, intuitive wayfinding helps all visitors, regardless of ability.
Universal design demonstrates a firm’s commitment to inclusivity and community, going beyond compliance to enhance human experience.
Partnering for Accessible Communities
At MFS Engineers & Surveyors, we understand that ADA compliance is about more than meeting regulations, it’s about creating safe, welcoming spaces for everyone. Our site/civil engineering team has the expertise to guide you through every step of the process, from evaluating your current site to designing new accessible features that meet both ADA standards and your project goals.
If you’re planning a new development, renovating an existing property, or simply want to ensure your site meets today’s accessibility standards, we’re here to help. Contact us today to learn how our engineers can provide solutions that make your property more accessible, functional, and compliant.