7.4 Freeway Driving, Ramp Merging, Shoulders & Interchange Types

7.4 Freeway Driving, Ramp Merging, Shoulders & Interchange Types

Quick Answer: Freeways are multi-lane divided highways with limited access. Enter using the acceleration lane to match the speed of freeway traffic, signal, and yield to vehicles already on the freeway. Ramp meters sit about halfway down an entry ramp — one car per green light, and running the red is illegal. If you drive slower than surrounding traffic, stay in the right lane. It is illegal to stop or park on an interstate freeway except in an emergency, and running out of fuel is not an emergency. It is illegal to back up or turn around on a freeway — miss your exit, take the next one.

---

1. Entering the Freeway

Entry ramps are short, one-way roads providing access to the freeway. At the end of most entry ramps is an acceleration lane that lets you build speed to merge safely.

The three-step merge:

1. Accelerate in the acceleration lane
2. Select a gap in traffic and adjust your speed to match the vehicles already on the freeway
3. Signal and move carefully into the traffic lane

Two rules that get missed:

• You must yield to vehicles already on the freeway. The merging driver is the one who adjusts.
• Do not stop on the ramp or in the acceleration lane unless it is absolutely necessary. Stopping destroys the speed you need to merge and puts you at the mercy of the driver behind you.

When there is no acceleration lane and a "Yield" sign is posted on the entry ramp, obey the sign — stop if necessary. Do not force your way into the lane of traffic.

---

2. Freeway Ramp Meters

Ramp meters are used on many freeway entry ramps in metropolitan areas to reduce traffic jams and crashes and to make merging easier.

Because metering releases vehicles one at a time, it spaces arrivals so each driver gets a usable gap — which is exactly why the one-car-per-green rule matters.

---

3. Freeway Speed and Lane Use

• Maintain approximately the same speed as surrounding vehicles when possible, but never exceed the posted speed limit
• If you are driving slower than other traffic, stay in the lane nearest the right side of the road
• To change lanes to pass or to leave the freeway, signal your intent and make sure your path is clear before moving over

Bus Use of Freeway and Expressway Shoulders

Transit buses and metro mobility buses are permitted to use the shoulder of a freeway or expressway, under strict limits:

• Only when main-line traffic speeds are less than 35 mph
• Bus drivers on the shoulder may not exceed main-line traffic speed by more than 15 mph
• Bus drivers on the shoulder may never exceed 35 mph
• Bus drivers on the shoulder must yield to merging, entering and exiting traffic, and to other vehicles on the shoulder

As a car driver, expect a bus on your right shoulder in congestion — that is lawful, and you must not block a bus merging back into the right lane.

High-Occupancy Vehicle Lanes

HOV lanes are for use only by motorcycles, buses, and vehicles carrying two or more people.

---

4. Freeway Interchanges

An interchange connects a freeway to a road or to another freeway through a series of ramps, letting you leave one road and enter another without disrupting traffic flow. The Minnesota Driver's Manual illustrates four designs:

+-----------------------------------------------------------------------------+
|                     FOUR MINNESOTA INTERCHANGE TYPES                        |
|                                                                             |
|   CLOVERLEAF ....... Four looping ramps in a clover pattern; all turns are  |
|                      made by curving right, no left turn across traffic     |
|                                                                             |
|   FOLDED DIAMOND ... Ramps folded to one side, used where land or a         |
|                      waterway limits the space available                    |
|                                                                             |
|   DIAMOND .......... The simplest form: straight ramps with signalized or   |
|                      stop-controlled ends on the cross street               |
|                                                                             |
|   DIVERGING ........ Traffic crosses to the opposite side of the bridge,    |
|   DIAMOND            removing left turns across oncoming traffic            |
+-----------------------------------------------------------------------------+

The Diverging Diamond Interchange

This design is worth knowing in detail because it is unfamiliar to most drivers and increasingly common in Minnesota.

• Traffic lanes cross over at each end of the bridge, so you briefly drive on the left side
• This eliminates left-hand turns across opposing traffic — instead of a sharp left, you veer to the left for access
• Pedestrians cross to the middle of the bridge and walk between traffic lanes with protective barriers on either side
• The design improves traffic safety and mobility and reduces overall traffic delays by up to 60 percent

The instinct to fight the crossover is the hazard. Follow the pavement markings and signals; they are guiding you deliberately onto the opposite side.

---

5. Stopping, Parking and Backing on the Freeway

It is illegal to stop or park a vehicle on an interstate freeway, except in an emergency. Running out of fuel is not considered an emergency, and you could receive a citation.

If You Must Stop for a Genuine Emergency

1. Park on the shoulder, as far from the main roadway as possible
2. Open the trunk and raise the hood, or tie a white cloth to the radio antenna or a door handle
3. Use hazard warning lights if you have them
4. If you have flares or reflectors, place them 100 to 500 feet behind your vehicle on the right edge of the main road
5. Stay with your vehicle if possible. If you must leave it, do not walk on the area of the highway reserved for vehicle traffic — that is illegal and extremely dangerous

Backing and Turning Around

It is illegal to back up or turn around on a freeway. The only exception applies to drivers of emergency and road repair vehicles, who may back up or turn around as necessary to perform their duties.

Emergency Vehicles on the Freeway

• Stopped on the shoulder with flashing lights: you must move a lane away if you can do so safely. If you cannot safely move over, slow down.
• Approaching behind you with lights and siren: move to the nearest side of the road and stop. Do not slam on the brakes or swerve into other lanes. Use your turn signal. Remain stopped until the emergency vehicle has completely passed, and look for additional emergency vehicles following it before pulling out.
• Stay at least 500 feet back from any firefighting vehicle.

---

6. Getting Off the Freeway

Know where you need to exit before you begin driving, and watch for signs about upcoming exits.

• As you near your exit, signal your intent to change lanes and move into the deceleration lane when you can do so safely
• The deceleration lane exists so you can slow down after leaving the through lanes, avoiding obstruction of faster traffic behind you — do not brake heavily in the travel lane
• If you miss your exit, proceed to the next one. Do not back up or make a U-turn to return to the desired exit