The DOT will quickly deny traffic signals if the intersection does not meet certain standards known as "warrants." Traffic-calming devices such as speed humps are not governed by the same restrictions.
Traffic signals do little to control speeding. They are designed to control the flow of traffic, not increase pedestrian safety. Traffic-calming devices are specifically designed to slow down cars.
A traffic signal will do little to stop reckless red-light running without consistent police enforcement. Traffic-calming devices are physically self-enforcing.