Greenfield Acres Neighborhood Association

As the signs with in our subdivision indicate - the speed limit is 25MPH. Please slow down. We have gotten many reports of people speeding through the neighborhood. Save a life, Drive SLOW!

What about speed bumps?

What are speed humps?
Speed humps are asphalt mounds placed on roadways for the purpose of slowing traffic. Speed humps are different than speed bumps, which are commonly seen in parking lots or on private streets. The City of Phoenix only allows speed humps on public streets.

Why are speed humps desirable?
Speed humps can help control speeding on local neighborhood streets: They can reduce average speeds by as much as 7 mph. Unlike traditional police enforcement, speed humps provide continuous service. They may also help discourage cut-through traffic by diverting it elsewhere.

Are there any drawbacks to speed humps?
Yes. Some of the disadvantages include:
?·Residents living near speed humps must tolerate increased noise levels as vehicles traverse speed humps day and night.
?·Vehicles may drive on sidewalks or through front yards to avoid speed humps.
?·Traffic may be diverted to previously quiet parallel streets in the neighborhood.
?·Emergency service response time suffers.
?·Motorized street sweeping equipment cannot be used at speed hump locations.
?·Speed humps interfere with street repaving, decreasing the effectiveness of both the speed hump and the new pavement surface.
?·Speed humps block the flow of drainage water on some streets and can cause flooding problems.
?·Speed humps require signing and striping, which some residents consider unattractive.

Is petitioning required?
Yes. Petitions help show whether strong resident support for speed humps exists. The City will designate an ''affected area,'' usually consisting of homes along the street where speed humps are proposed. Residents must obtain support from at least 70 percent of residents in the affected area, and must obtain support from every resident whose home is within 100 feet of a proposed speed hump.

Where can speed humps be installed?
Speed humps are permitted on local streets in residential areas where the speed limit is 25 mph. However, speed humps are not permitted:
?·On streets where drainage water flows down the center of the street
?·On streets regularly used by buses, trucks, or emergency vehicles
?·Within 200 feet of a STOP or YIELD sign
?·On streets dustproofed with Bituminous Surface Treatment (BST) or on alleys
?·On or near steep grades or sharp curves
?·Closer than 500 feet apart
?·On collector streets
Who pays for speed humps, and how much do they cost?
Each speed hump, together with required signing and striping, costs approximately $1,200 to install. Depending on a street's average speed, residents pay either the full $1,200 cost or a portion of the cost, as shown below. Residents can collect and pay their portion of the cost of speed humps any way they like.

Average speed on a street* Cost
25 mph or less $1,200

*Speed thresholds can be reduced by 2 mph for speed humps within 250 feet of a park or school.

How can our neighborhood begin the process of installing speed humps?
The first step in the process is a traffic study, which will show the average speed of vehicles using a street. To request a study, residents should print out, complete, and return the attached ''Speed Hump Study Request'' form and obtain signatures representing ten households on the street. A separate form should be completed for each street where humps are to be considered. Signing this form does not commit residents to support speed humps, nor does it commit them to provide funding in the future.

Traffic calming devices

In Phoenix, the city opens up a tool box of traffic calming devices to citizens, from which they can pick and choose their weapon.

''If it's speed, you can put in a chicane or woonerf or choker or speed humps. You can put in diverters,'' says James Matteson, street transportation director. ''There are dozens of different physical devices or technologies or controls that you can use. It's the engineering approach.''

But the key in Phoenix is that citizens have to meet the city halfway, both in planning the project and footing the bill.

The neighborhood has to work as a partner with the city's Neighborhood Traffic Management Team, a slate of six engineers and technicians who will direct the citizens through the process and technologies. The neighborhood selects the plan, Matteson explains. The city supplies the expertise.

''We do the technical work free, but if they want physical devices installed, the neighborhood has to pony up half the cost,'' he says. ''They have to participate in the cost to calm the traffic.''

Matteson says this method was designed after seeing what didn't work in other cities, particularly the conflict between those who love traffic calming, and those who don't.

''We realized that if the neighborhood did not buy into it, they would not support it,'' he explains. ''If you give away the devices for free, they want everything in the world. If you make them pay for half, they become a little more careful. They think long and hard before being willing to install very expensive traffic calming devices.''

The city sets aside $100,000 annually to match citizens' money for traffic calming devices. Neighborhood projects can be as low tech as signage, changing speed limits, or installing speed humps. Or, he says, it could be a very expensive reconstruction in a very large neighborhood. ''Every case is unique,'' he says.

Addressing growth, city planners hope developers will incorporate these devices into their subdivisions. The traffic calming team, along with staff from planning, developer services, fire, police and public works, devised a plan for developers to follow, ''so as to not keep repeating the mistakes of the past.''

New subdivisions are showing up with narrower streets, set-back sidewalks, shorter streets and configurations that stymie cut-through traffic.

''Traffic calming is whatever you want it to be,'' he says. ''Traffic engineers have lots and lots of tools in the old tool kit. Do it before the problem exists.''

Contact: James H. Matteson
Street Transportation Director
602/262-6284

A recent discssion with the City of Phoenix indicated that Speed Humps are not recommeded as traffic control measure due to speed humps tend to block the flow of drainage water on our streets and can cause flooding problems.