The Institute of Transportation Engineers published a fact sheet titled Fact Sheet 6: Designing Avenues and Streets in Residential Areas. It’s a very good reference for anyone involved with the design of new neighborhoods. Table 1 shows recommended design element ranges derived from the report based on the location of the neighborhood
Table 1 – Recommended Transportation Design Elements for NeighborhoodsIn Minnesota, the statutory speed limit on local streets is 30 mph. Following are other design guidelines based on this speed (note the recommended practice also provides guidelines for other speed limits):
- Minimum stopping sight distance = 200 feet
- Minimum centerline horizontal curve radius = 300 feet
- Maximum grade in rolling terrain = 8% (2% at intersections)
- Clear sight distance provided at intersections without traffic control = 140 feet
- Corner radius at intersecting streets at 90 degree angle = 15 feet
- Minimum distance between tee intersections = 125 feet
The Fact Sheet provides other standards such as sidewalk and intersection characteristics and is a handy reference for those looking for general standards while working on neighborhood design projects. One topic not covered in detail is where to put signs within neighborhoods. Given the budget pressures faced by agencies and research about the effectiveness of signs, I encourage you to minimize the use of all signs in new neighborhoods other than street name signs.
Are you looking for great tools? Check out The Engineer’s Guide to Citizen Traffic Requests a collection of tried and true processes and templates to respond to common citizen traffic requests. This go-to manual will shave hours off the time it takes to respond to traffic-related inquiries from the public, and help create consistent correspondence throughout your department.