Did you ever drive onto an on-ramp and go around the bend only to see that the highway is actually a linear parking lot? Didn't you wish that you had a heads-up with that information so you could have not taken the ramp and maybe had a meal or made a pit stop while planning an alternate route (or time) for the trip? DOT can place a traffic camera showing live traffic on the highway (attach it to the bridge) and via an ITS cable, connect it to a screen placed at the sign leading to the ramp. That way, drivers can see the traffic flow on the highway prior to taking the on-ramp. If the traffic is moving, they can take the ramp. If there is a traffic jam, the driver can choose to take the ramp anyway or not to take the ramp.
With solar power, this can be a self contained system. Parts list: traffic camera, cable, weatherproof impact-proof tamperproof screen, power source, and construction permits.
The cost of the system will come down once someone designs and packages it, considering the quantity of on-ramps statewide, nationwide, continent-wide, and world wide.