The phrase "blind crests" refers to hills or slopes that are difficult to see or anticipate because they are out of sight until you reach the top. Full definition
This is slow - speed, tiptoe terrain dotted with blind crests and even blinder corners, rutted pavement, crumbling valley - side shoulders, and impromptu mudslides. (automobilemag.com)
They involve cornering at full acceleration while positioning the car in readiness to blow over the top of blind crests. (automobilemag.com)
No matter how good they might be, no lights — laser or otherwise — can see over blind crests. (automobilemag.com)