I have been reading a lot of urban design books. Most of them are targeted at cities. Places like LA or SF, with an urban core that has high potential for walkability and transit, but has been ruiend by car-dependant development.

For example in Walkable City Rules Jeff Speck suggests curb cuts for driveways should not be allowed. Not allowing driveways may make sense in SF, but it is a hard sell here in Mountain View.

The reality is that people have cars here, and will have for the foreseeable future. Reducing VMT Per Capita is reasonable. Reducing vehicle ownership will take more time.

Wait, Why Are Driveways Bad?

Most lots in the USA have a driveway, and most people have never known anything else. It is normal, and we don’t think about it.

But driveways have problems. And like most problems associated with suburbia, they only become a problem when ubiquitous.

Driveways Are Dangerous

Driveways are intersections. Intersections are where most accidents happen. Traffic engineers know the problem with intersections, that is why they design suburbs with long winding streets and few intersections. But they don’t think about the fact that every driveway is an potential point of conflict between people driving, people walking and people riding bikes.

At low enough speeds this is not a problem. But nearly all US roads are designed for speeds where fatal accidents occur. Even when posted limits are lower, people tend to drive at higher speeds on roads that were designed for higher speeds.

Street parking exacerbates the problem. Street parking removes visibility. People turning into driveways cannot see pedestrians, especially children. People turning out of driveways cannot see oncoming traffic until they are already partially in the travel lane.

For streets with bicycle lanes the problem becomes even worse. Putting the lane on either side of the parked cars is dangerous. The only safe solution is to remove street parking entirely. But middle density areas already have high demand for street parking.

As densities grow more lot splits, roommates, and ADUs will increase the number of cars parked in driveways and along the streets. People who have lived on California St for over 20 years tell me it used to be a safe street where children could play. It is hard for me to believe.

Driveways Slow Traffic

You cannot have a smooth flow of traffic when there are driveways every 40 feet. Too many cars slowing down to turn. Sometimes cars will stop completely, especially when making left turns

Because of this driveways and off-street parking are antithetical to traffic flow. Any street that is supposed to move large volumes of traffic should not have off street parking.

Off street parking and driveways only work when speeds are low and attention is paid to lines of sight. This means no street parking near driveways and restricted left turns.

Driveways Cover Space

Current R1 Zoning Standars require a minimum of 9x20 paved driveway leading to a minimum 9x20 paved and enclosed garage. Not only dies this reduce the amount of livable space, it also reduces the amount of green space. In a place where space is a premium, it is unconscionable that a private landowner is forced by law to build a garage and driveway.

In multifamily and multi-home developments, paving the way to everyone’s garage can cover an even higher percentage of the lot. Most of the older apartment buildings have paved nearly all the lot surrounding the structure.

So Where Should We Park, Then?

The current approach in Mountain View is still to have a single driveway per development. Since most new developments are large, multi-lot things it is a marginal improvement.

Large developments can have their own problems, but the most obvious one is that a driveway shared by many residents is a road in all but name. Usually these lack any kind of amenities for street life or safety, feeling about as comfortable to walk along as a mall parking lot.

I propose a better approach: bring back the alley.

What’s so Great About Alleys?

The center of my hometown is a grid. Most blocks are divided in half by a dirt alley. This used to be the pattern all over the US, but no longer. Allies are a relic of the past.

In The Geography of Nowhere James Howard Kunstler says fire departments are responsible for the death of the alley.

But I think alleys solve our parking problem, and have some other benefits as well. We can buy some smaller trucks to keep the fire department happy.

Alleys For Garages

If you must have a garage, build it on the back of the lot. This is how things used to be done. Porch and front door face the street, garage in the back.

Alleys are narrow and designed for low speeds. There is no reason to be in the alley unless you live on the block. Low traffic and low speeds eliminate the dangers of off-street parking.

Moving garages to the back of the lot makes the front of the lot a safer place to travel, whether by car, bicycle or foot.

Alleys For Garbage

A side benefit, but putting you cans in the alley is a much better solution than having them out by the curb one day a week. Cans on garbage day only make sense in low density areas where there are few pedestrians and plenty of street parking.

In the alley they are not in the way of anyone parking and not blocking bicycle lanes or sidewalks.

Allies for ADUs

Another thing that used to be common was to build an ADU above the garage in the rear of a lot. With SB9 there will be many more ADUs built.