This is a residential area. No need to change the speed limit.
Drivers are out of control.

A city CAN put up speed bumps legally. New Haven has them on some streets BUT there must be a sign warning people where they are.

Municipalities can only permit speed bumps on unclassified local and private roads.
Marshall Lane has a Federal Functional Classification designation of "Collector" (see attached map). In 1993 Mayor Schlesinger accepted a Federal Highway Administration grant to upgrade this roadway. Derby agreed to abide by the approved road design and is therefore not permitted to install speed bumps on Marshall Lane.
Derby can petition its planning region to reclassify the roadway, although it is far from certain that the request would be granted. In such a case, Derby might then be liable to repay the original grant of several million dollars to the FHWA if it deviated from the design. Installation of speed bumps would constitute a serious deviation.
Ryan is correct. A 25 mph speed limit will rarely be enforced because it is so slow. A reasonable posted speed limit for this road (say 35-40 mph) would lead to a greater likelihood that it would be strictly enforced and the average speed for drivers would likely drop.
The design speed (always higher than the posted limit) for this road is 55 mph.

Thankfully, Marshall Lane has two stop signs that slow traffic down, somewhat. As far as speed limits are concerned, police generally enforce anything over 10 miles over the limit. Failure to enforce speed linits are totally on they city itself. It usually take a few deaths before anything is done, as in past instances.

Speed humps work. I work for a town that has them on a road very similar to marshall lane. Too many accidents and racing side by side on this road. Someone is going to get killed..

I want to thank planner for the VERY detailed and helpful explanation. Speed bumps may work, CLEARLY the grant accepted by Derby in 1993 makes the city unable to install them on Marshall Lane. End of that discussion.

That said, I have always felt if posted speed limits were REASONABLE drivers would be more likely to abide by them. Instead, far too many local roads get a "25 MPH" sign slapped on them which most of us know is not reasonable. Have you driven at 25 MPH? Someone will ask you if you're having car trouble not to mention cars backing up behind you laying on their horns.

I roll my eyes all the time at these standard 25 MPH signs that are far too slow and cause drivers to simply ignore speed limits. There are portions of Route 8 that STILL say "55 MPH" Really? When was the last time a vehicle traveled on a highway at 55 MPH?

I agree with planner. Post a 35-40 MPH limit on Marshall Lane and watch how people realize that it makes sense and slow down. 25 is a joke!