Driveway Approaches & Culverts in Rochester Hills, MI

Driveway approaches and culverts sit in the road right-of-way, between your property and the pavement of the street. In Rochester Hills, the approach is built to a published city specification that is stricter than most people expect, and on uncurbed roads it crosses a roadside ditch through a culvert pipe. Both take the weight of every car, the push of every plow and the runoff from the road. When an approach breaks up or a culvert collapses, the damage spreads up the driveway.

What the Rochester Hills spec calls for

• Residential asphalt approach: 6 inches of hot mix asphalt over 4 inches of 21AA aggregate base, built as a 2-inch HMA 13A wearing course over a 4-inch HMA 3C leveling course placed in two 2-inch lifts.
• Residential concrete approach: 6 inches of 3,500 psi concrete over 4 inches of 21AA base.
• Commercial asphalt approach: 9 inches of HMA over 6 inches of 21AA base.
• Alternate base: recycled asphalt base may be considered with the City Engineer's approval if it matches 21AA strength.
• Slopes: 2 percent minimum; 8 percent maximum on roads posted 40 mph or more and 10 percent on roads posted 35 mph or less; no more than 2 percent where a sidewalk or pathway crosses, for ADA.

Widths and flares

The spec ties approach width to the driveway: a one-car approach of 12 to 15 feet at the right-of-way flares to 18 to 21 feet at a local street; a two-car approach of 16 to 25 feet flares to 22 to 25 feet. Approaches on major streets are wider at the road, up to 36 feet. Circular drives need at least 80 feet of frontage, with approaches at least 45 feet apart, centerline to centerline, entering at 90 degrees.

Culverts and ditches

Where a ditch runs along the road, the city calls for a culvert of at least 12 inches in diameter in 16-gauge galvanized corrugated metal pipe, with at least a foot of cover from the top of the pipe to the top of the driveway, extending at least 3 feet beyond the driveway on each side. Ditches are limited to 2 feet deep and set side slopes. A culvert that has rusted through, been crushed by a truck or filled with silt sends water over or under the approach, and the asphalt above it fails.

Who owns your road

Not every road in the area is a city road. County roads fall under the Road Commission for Oakland County or, across Dequindre, Macomb County, and state highways under MDOT. Rochester Hills notes that commercial driveways must at least meet RCOC and MDOT rules, and that city requirements may exceed them. We find out who controls the road in front of your property and plan the approach and any permit around that.

When the approach is all you need

Sometimes the driveway is fine and only the approach has failed, often from plow damage, a sinking culvert or heavy trucks. We can rebuild just the approach and tie it into the existing driveway with a clean saw-cut joint.