I live near this intersection and see this every day. I don't think people who disregard stop signs and a blinking red light will adhere to any other traffic signs, but can't hurt.
There's also the issue of people who park illegally on the corners, making it difficult to see any pedestrians (or vehicles) who might be crossing the intersection.

Has a sign been placed here?

This is a signalized intersection, therefore, the department will not be placing an in-road pedestrian sign at this location.

Hi all,

Traffic controls on Elm, Edgewood and Chapel have been requested by a large group of citizens: see http://nhregister.com/articles/2011/08/28/news/new_haven/doc4e5940934abb6722446887.txt. The group acknowledges that in-street signs won't work on these larger, two-lane one way streets, or on many of the cross streets (like Ellsworth) because they have traffic signals.

However, this means that alternative solutions are needed.

Perhaps a more permanent pedestrian median system, or a traffic circle, should be constructed here. These types of lower-cost measures can be incredibly effective: See http://www.usroads.com/journals/rmej/9801/rm980102.htm

If speeding and disregard for pedestrian safety continue to be an issue at Elm and Ellsworth, the neighborhood should fill out and submit a "complete streets" request form at http://www.cityofnewhaven.com/Engineering/completestreets.asp. Getting these types of requests on the official public record will really help the city improve the safety of these crossings over time. If you need help completing the form itself you may want to contact your local alderperson or newhavensafestreets at gmail.com. Get as many local residents and Aldermen as possible to sign your request form.

Good luck!