When mobility meets fire safety…

Houston fire truck
Apparently, Houston’s current planning ordinance for shared driveways has room for improvement, and not always enough room for fire trucks. One of the many benefits of living in the City of Houston is protection by the largest professional Class I fire department in the world. But some of the new townhouse developments built since 1999 were planned such that one or more units at the back are not reachable by fire trucks.

tall townhouse photo
Chapter 42 (2.4 mb PDF) of Houston’s Code of Ordinances sets requirements for different types of development. Since 1999, it requires “private streets” for multi-family residential complexes — apartments — to be at least 28 feet wide. “Shared driveways” for single-family residential developments — townhouses — were deemed adequate at 16 feet.

As originally envisioned, 16-foot driveways worked well for small townhouse developments with two or perhaps three units on one 5,000 square foot lot. Even the back-most unit would be just 60-80 feet from the curb.

But in the years since the ordinance was written, developers have assembled multiple-lot parcels to build many more townhouses in the same place. In these larger developments, a shared driveway may extend 200 feet or more, or make 90-degree turns with unforgiving geometry, which is a problem. Some of these driveways are unnavigable by a Suburban or large pickup truck, never mind a fire truck. Further, the ordinance allows the second story of the structures to be cantilevered and extend 4 feet over the driveway beyond the first floor.

City of Houston Planning Dept logo
Recent meetings of the Houston Planning Commission’s Mobility Subcommittee surfaced this issue. According to Mike Shrum of the Houston Fire Department (HFD), a fire in a multi-story town house requires a ladder truck, so they can rain water down on top of the fire. The smallest ladder truck they have is 9 feet tall and 9 feet wide, with “outriggers” that extend 5 feet on each side to stabilize the truck. The first problem: you cannot plant a 19-foot-wide ladder truck in a 16-foot-wide driveway. The second problem: ladder trucks don’t turn corners well.

shared driveway development plan
Consider the plan shown at right (click the diagram for a larger, detailed plan view) for a 21-unit townhouse development along one of Houston’s bayous. Vehicles enter the site via gates from a through-street on the left and from a dead-end street on the right. Most of the town houses are along the middle driveway which has no direct gate access to the street. According to HFD’s Shrum, it would likely be very difficult to fight a fire effectively in units 7 or 8 (noted in red box), because they are too far from the street to reach directly, and the driveway is too narrow to get to them.

I would guess that most every Houston homebuyer assumes protection from the fire department as a given. But many would be dismayed to learn that in practice, the current ordinance allows some homes to be designed and built that are beyond the reach of the fire department. This has serious implications for home owner liability, property insurance rates, and requirements for protective devices like smoke detectors and sprinkler systems.

It doesn’t have to be this way.

shared driveway better plan
Consider: the site above could be planned differently. Structures could be arranged further apart to allow safe access to all of them. Done this way, it may not allow the same number of units, and a developer may argue that it will reduce the profitability of the development. But I doubt the intended homeowners will find that the most pressing concern.

This shared driveway issue is a perfect example of the current opportunity to improve land planning in Houston. It’s not about telling property owners how to use their property. Good planning is about ensuring projects are built in a way that minimizes unintended consequences.

For the future, the Mobility Subcommittee is discussing possible revisions to Chapter 42′s shared driveway ordinance. But for now, all of us should be sure to install smoke detectors and check the batteries periodically!

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