Roads, Access & ADA
Access & circulation
- Driveways / curb cuts require approval from the road authority, with adequate sight distance.
- Traffic studies may be required; the agency can require off-site improvements (turn lanes, signals) — a significant cost.
- On-site drive aisles, fire lanes, and turning radii must meet fire-department and code standards.
Parking
Zoning sets minimum (and sometimes maximum) parking counts, stall dimensions, and accessible-space requirements.
ADA / accessibility
Public and commercial sites must meet ADA standards: accessible routes, parking, ramps, slopes, and entrances. Bake accessibility into the grading and layout from the start — retrofitting is costly.
Going Deeper (Intermediate)
Roads/streets must meet design standards (width, geometry, pavement section), connect to public roads, and provide ADA-compliant pedestrian access (sidewalks, ramps, slopes).
Advanced / Pro-Level
The standards and the exactions:
- Street classification (local/collector/arterial), geometric design (sight distance, turning radii, grades), and a pavement section engineered to traffic + subgrade strength (R-value).
- Public vs. private streets (who maintains — city or HOA).
- A traffic study may force off-site improvements (turn lanes, signals) — costly exactions.
- ADA/PROWAG: curb-ramp running slope max 8.33% (1:12), cross-slope 2%, detectable warnings.
- Access permits from DOT/county for connections. Off-site road improvements are a frequently underestimated cost.
Practice Challenge
A traffic study for your subdivision requires a new left-turn lane and signal at the entrance. What is this called and why does it matter? (Answer: an exaction / off-site improvement condition — the cost of public road improvements imposed as a condition of approval; these can be large, underestimated costs that must be in the pro forma, and they're common outcomes of the required traffic study.)
In Practice
A traffic study triggers a required turn lane that wasn't in the budget — a six-figure surprise. Access and offsite improvements can be major costs.
Common Mistakes to Avoid
- Ignoring access and traffic requirements
- Not budgeting offsite road improvements
- Skipping ADA in the layout
Takeaway: Bake access and ADA into the layout from the start; retrofitting is costly.
Educational content — not legal, engineering, or financial advice. Requirements vary by jurisdiction; always confirm with the local authority and your professional team.