There is well established precedent on how to reduce speeds on highly used residential roads. It's called "Traffic Calming". Essentially, you redesign the road so that it is narrower, curvier and gives better access to pedestrians and bikers. The basics of Traffic Calming can be found here:
Generally, urban roads that have traffic where it's even possible to move at 50 mph are straight, wide and flat. That is definitely the case with Locust Ave, as seen below.
Some suggestions for slowing traffic on this street might include:
- Put curb extensions at the sidewalks to reduce the distance that pedestrians have to walk to cross the street. This also makes the intersections tighter for cars, requiring them to slow down.
- Currently, parking is only on the left side of the street. About every half a block alternate parking between the left and the right sides causing the traffic to have to curve back and forth. This will slow down the traffic.
- Mark the parking with stripes, making the traffic lanes look smaller.
- If there is room, add another bicycle lane to the left side of the street.
Here is an example of traffic calming.
Although this street is in a more dense urban area (Cambridge, MA) than Locust, it used to look similar to it. All parking was on one side, and there were no curb extensions. Now you can see the tightened intersections and the curvy traffic lanes. Speeds have dropped significantly on this road. It's worth a try.