Driving the Grid Over the Hills

San Francisco's street grid was surveyed onto the peninsula largely without regard for what was underneath it, which is why streets run straight up gradients that any sane road designer would have contoured around. The result is a city where ordinary intersections sit at the top of crests steep enough that you cannot see the cross street until you are in it.

The blind crest is the hazard

Approaching an intersection on a steep upgrade, your line of sight goes over the intersection rather than into it. You cannot see a pedestrian stepping off the far curb, a car edging out, or a cyclist descending the cross street. And the driver on the cross street cannot see you either, for the same reason in reverse.

The only reliable answer is to arrive slowly enough to stop for whatever turns out to be there. On the steep blocks, that means treating every crest intersection as if something is in it, because periodically something is. The same applies to driveways and garage entrances on a grade, where a car nosing out has no sight line at all.

Descending, and the thing that ruins brakes

Riding the brakes down a long steep block heats them, and heated brakes fade exactly when you need them most, at the bottom. Use a lower gear — yes, in an automatic, and yes, in most electric vehicles, where stronger regenerative braking does the same job. Let the drivetrain hold the speed and use the brakes in firm short applications rather than as a constant drag.

If you smell hot brakes, that is not a smell to drive through. Stop somewhere safe and let them cool.

Curbing your wheels is the law, not folklore

Vehicle Code section 22509 provides that no person in control of a motor vehicle shall permit it to stand unattended on any grade exceeding 3 percent within a business or residence district without blocking the wheels by turning them against the curb or by other means. Three percent is a much gentler slope than most people picture, so this applies across a great deal more of San Francisco than the postcard hills.

The direction people forget:

• Facing downhill: turn the wheels toward the curb. If the car rolls, the front tire finds the curb immediately.
• Facing uphill with a curb: turn the wheels away from the curb, so a rolling car backs into it.
• No curb at all: turn the wheels toward the edge of the road in either direction, so the car leaves the roadway rather than rolling down it.

And set the parking brake every time, before you take it out of gear or out of park. A parking pawl is not a parking brake, and a car that rolls away and hits something is a liability claim with your name on it.

Hill starts and the car behind you

Most modern vehicles hold the brake for a moment when you lift off on a grade. Older ones do not, and the roll-back into the car behind is one of the more common low-speed collisions in this city. If you drive something without hill-hold, leave more space in front of you than feels necessary when you stop on a grade, and use the parking brake to start if you need to. The driver behind you should be doing the same — but you cannot make them.

The scrape nobody counts

Steep driveway aprons and the transitions where a hill street meets a flat cross street are where low cars lose their front air dams and exhaust hangers. It is cosmetic, it is annoying, and it is almost always below a deductible, which makes it a repair rather than a claim. Approach the transition at an angle and slowly, and most of it never happens.

Wondering whether your deductible is set where it should be? That is worth ten minutes.