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Maine Local Roads Center
SPEED
HUMPS VS. BUMPS
In
an effort to get drivers to slow down, many towns have considered,
or been asked by citizens, to construct speed bumps, or humps, or
tables, etc on public roads. If these public roads are townways,
then the decision can be made by the municipal officers. If these
roads are State Highways or State Aid Highways (inside or outside
urban compact areas), then these controls are generally not allowed.
In
contemplating this decision, a town must consider several related
issues. If the road is planned for reconstruction or it is a new
subdivision road, then a "different" design could be done that incorporates
traffic calming measures in the geometry so that humps or bumps
are not needed.
However,
if the road exists today and people are looking to the town to slow
drivers down, then the municipality has a few options. First, you
need to step up enforcement of current ordinances and speed limits
(officially lowering the speed limit or erecting unwarranted STOP
signs is not the right approach). Second, the same geometric design
options exist which could mean obtaining right-of-way and spending
some significant dollars to reconfigure the road. Third, the cheaper
option is to construct some speed humps or tables. Do not construct
speed B umps which are the shorter, more abrupt obstructions
that you see in parking lots and bank driveways and private roads.
A speed H ump (or table) is a viable option, if designed
correctly, that will slow traffic to a certain level. They usually
are 12 to 15 feet long and 4 inches in height. Usually, they are
painted to identify a vertical change in the road and there should
be advance warning signs from both directions. There are many municipalities
across the country which have successfully installed these humps
even though they create loads of local controversy. You could choose
to install permanent bituminous ones or you could buy portable rubber
ones --- there are pros and cons to each type. A town will probably
will not find a lot of positive reaction from the folks who have
to drive plow trucks, or ambulances, or fire trucks over them.
From
the legal perspective, it's important to pass a "traffic ordinance".
As stated in State law 30-A MRSA Section 3009, "the municipal
officers have exclusive authority to enact all traffic ordinances
in the municipality.". Therefore, the Board of Selectmen (or
Town Council) can authorize the use of these traffic control devices.
From a liability perspective, anyone will sue for anything and a
speed hump could be viewed as a "highway defect". However, State
law 23 MRSA Section 3651(1) states that "legal objects
are not defects. Trees, structures and other things which exist
in accordance with municipal ordinances are not defects in a public
way". It may also be difficult to prove that they are dangerous
especially when they have been used successfully by some many entities
in the US and in foreign countries. If the Town decides to start
allowing these humps, I would want to make sure that they are properly
designed and marked and signed according to the standards in the
MUTCD.
It's
important to consider all the ramifications before you decide to
open this "can of worms". Once you install one hump, many other
folks will want them on their road.
Speed
Humps:
- Are a gradual raised area in the pavement surface extending
across the entire travel width
- Typically, 3 to 4 inches in height with a travel length of 12
to 15 ft
- Have evolved from extensive research & testing
- Create a gentle vehicle rocking motion which results in most
vehicles slowing to 15 mph at each hump and 25 to 30 mph between
properly spaced humps in a system
- Need to be designed and installed with proper planning and engineering
- Effective at controlling speeds without creating accidents or
imposing unreasonable or unacceptable safety risks
Speed Bumps:
- Are an abrupt raised area in the pavement surface
- Effective at controlling speeds on low volume, low speed roads,
especially private driveways and parking lots
- Typically, 3 to 6 inches in height with a travel length of 6
in. to 3 ft
- Cause significant driver discomfort at typical residential speeds\
- Cause vehicles to slow to 5 mph or less at the bump
- Maintenance headaches especially for plow trucks
Much more information can be found on "traffic calming"
at the following links:
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