The City of Coppell no longer allows speed bumps/humps to be installed on any public street. The Fire Department, the Police Department, and the Public Works Department have considered them in the past and discussed them with City Council and the City has decided not to use them.
Reasons to Not Install Speed Bumps
In short, they are a hindrance to emergency vehicles, cities have been held liable for damage caused by them, they do not always have the intended effect (because some people will speed up between them), and they are very divisive within neighborhoods. Some residents on a street will want them, but others will not, and residents of nearby streets will not want traffic diverted to their street.
Studies have shown that for the humps to be effective, several must be installed on a street at a specific distance apart, which impacts more residents and further slows down emergency vehicles (it is estimated that each hump delays emergency vehicles 10 to 15 seconds).