Chapter 4 - Elements of Design

4.3. Vertical Alignments

4.3.6. Vertical Grade Changes at Intersection

If it is impractical to match the elevation of an intersecting road, the crossroad should be reconstructed for a suitable distance using adequate vertical geometry to make the grade adjustment. In general, a 2% maximum tangent grade break is allowed at the edges of signalized intersections to allow vehicles on the crossroads to pass through an intersection on a green signal safely without significantly adjusting their speed. A 4% maximum grade break is allowed in the center of an intersection corresponding to the 4% crown breakover associated with a crossing road. For the edges of unsignalized or stop condition intersections, a maximum tangent grade break of 4% may be employed.