Miami-Dade county has installed ramp lights at several I-95 entrances to lessen traffic congestion. One of the concerns is the probability of rear-end collisions.
http://miami-info.com/news/2009/02/02/ramp-lights-will-control-car-flow-onto-i-95-in-miami-dade/
Ramp lights will control car flow onto I-95 in Miami-Dade
The days of freely entering some of the busiest sections of Interstate 95 in Miami-Dade County are coming to an end. Starting Wednesday, motorists must wait for a green light at an entrance ramp to merge in.
Its all part of a master plan to manage congestion on one of Floridas busiest expressways.
Commuters will encounter traffic signals at eight northbound I-95 on-ramps between Northwest 62nd Street and the Golden Glades interchange during the afternoon rush hours.
But like the new northbound variably priced toll lanes that kicked off in December, enforcement of the on-ramp signals is certain to launch controversy and confusion for South Floridas notoriously short-tempered drivers.
Its going to be a learning curve, said Lt. Pat Santangelo, a spokesman for the Florida Highway Patrol which plans to post a trooper at every affected ramp to make sure drivers obey the signal.
It will be a momentous shift for South Florida commuters, long accustomed to zipping onto I-95 without much thought.
Drivers will be required to stop on the ramp and wait for the light to turn from red to green just like at an intersection.
Violators who run the ramp signal may face penalties, including a ticket for $160 and three points on their license.
Police are urging drivers to pay extra attention as they enter I-95. Some drivers may not stop and others, unaccustomed to red lights on an interstate ramp, may slam into those who obey the signal.
Santangelo said FHP hopes drivers will adjust.
We are hoping that the same thing happens as happened with I-95 express lanes that after the initial chaos people understood what they were for and the confusion diminished, Santangelo said.
CONFUSION LIKELY
Some South Florida commuters are ready for the change, and are bracing for confusion with a system that has become common in other parts of the country.
The potential for rear-end collisions is huge, said Andre Pierre, an immigration attorney and North Miami mayoral candidate who frequently drives on northbound I-95. I went to look at one of the signals on the 62nd Street ramp the other day, and I realized that the main problem is that some drivers may not stop and rear-end others.
By regulating when vehicles enter the highway, traffic managers say driving on the busy stretch will be faster, more comfortable and safer.
Congestion occurs when the number of vehicles on a road exceeds its capacity and when more vehicles entering the highway through on-ramps disrupt the flow of traffic already inching along.
Platoons of vehicles often speed onto the highway, merging at will and cutting off vehicles already on the expressway. These vehicles then suddenly stop, slow down or attempt to block incoming vehicles in a dangerous struggle to get ahead in congested lanes.
Traffic managers often cite unregulated merging as a chief source of congestion, crashes and road rage. Under the new system, traffic managers hope to at least ease the merging madness.
Ramp signaling will make it a better driving experience when you are not playing chicken with 20 cars entering the freeway at the same time, said Rory Santana, Florida Department of Transportation manager for Intelligent Transportation Systems in Miami.
Santana, who oversees the ramp signaling system, said that, in general, local drivers will not have to wait long to enter I-95 anywhere from a seconds to a few minutes.
As the system is currently configured, the light will alternate between red and green, allowing one or two vehicles at a time onto the expressway.
If traffic is light, said Santana, the red will cycle into green more frequently than when traffic grows heavier. Santana said vehicles waiting at the ramp will receive a green signal every four to 15 seconds.
The wait, he said, will be longer, perhaps a couple of minutes, for vehicles waiting farther back in the line, not unlike a delay at any other normal signalized intersection.
MINIMIZING BACKUPS
Santana said traffic managers will try to minimize possible ramp backups spilling onto surrounding roads or neighborhoods.
Sensors under the ramps and expressway lanes, along with surveillance cameras, will determine the wait for drivers and speed up entries if ramp backups grow beyond tolerable levels, Santana said.
Elsewhere in the country, ramp waits in some cases in the past have been estimated at 20 minutes for the last vehicle in the queue.
For now, Santana said, the plan calls for installing ramp signals only along I-95 in Miami-Dade eventually regulating vehicle entries along northbound and southbound ramps to Ives Dairy Road.
In Minnesota, an initially unpopular ramp signaling program was briefly shut down. However, when that was done, expressway speeds decreased by 26 percent. Once the signals were reinstated, highway speeds picked up again.
THEY want to go faster than that and THEY will do ANYTHING to get around you. I would always tell my wife when those drivers come speeding up in the left lane to speed up close to the driver in front of you so they cant squeeze in there. After all, we are all in a hurry, right? We ARE in the fast lane, and we WERE there first. Right? 
I would be petrified! (Luckily I've never had to get off and back on!)
