• Bicycles, mopeds, and pedestrians are specifically prohibited from using the Autobahn, as are any other vehicles with a maximum speed rating of less than 60 km/h (36 mph).
• Passing on the right is strictly prohibited!  Slower vehicles must move to the right to allow faster traffic to pass, and drivers should stay in the right lane except to pass.  When passing, you must do so as quickly as possible, and it's in your best interest to do so lest you become a hood ornament on that Porsche that was just a speck in your mirror a second ago and now is close enough for you to see the look of distain on the driver's face.  You are, however, allowed to pass on the right in heavy traffic when vehicles have started queuing, but only at a slow speed.  You may also pass on the right while you are still in the designated acceleration lane upon entering the Autobahn.
• Stopping, parking, U-turns, and backing-up are strictly verboten, including on shoulders and ramps (except for bonafide emergencies of course.)
• Entering and exiting is permitted only at marked interchanges.
• Traffic entering the Autobahn must yield to traffic already on the Autobahn.
• On Autobahn sections with three travel lanes, trucks over 3.5 tonnes and any vehicle with a trailer are prohibited from using the far left lane.
• During traffic jams, motorists in the left lane are required to move as far to the left as possible and those in the adjacent center or right lane must move as far to the right in their lane as possible, thus creating a gap (Rettungsgasse) between the lanes for emergency vehicles to pass through.
• If you have a breakdown or accident, you must move to the shoulder if possible and place a warning triangle 200 meters behind the scene.  You must report the incident to the authorities using the nearest emergency phone (see below).
• It is illegal to run out of fuel on the Autobahn.  Technically, there is no law specifically against this, but it is illegal to stop unnecessarily on the Autobahn and this law is also applied to people who run out of fuel as such an occurrence is deemed to be preventable.
• There are no tolls for passenger vehicles to use the Autobahn.  However, trucks now must pay a per-kilometer fee.  This fee is collected electronically.

In addition to the official laws, most drivers follow the following customs:

• Motorists at the rear of a traffic jam usually switch on their hazard blinkers to warn approaching traffic of the slowdown.
• Many drivers flash their high beams ("Lichthupe", or "light honking") or switch on their left turn signal to politely (or not) request that you vacate the left lane to let them pass.  There are conflicting opinions about whether this is legal or not and why, but there are reports that drivers have been cited for doing this.  So while there is no specific law regarding this, it appears that such actions can be construed to violate Germany's coercion laws, so do so at your own risk.

Despite the widespread belief of complete freedom from speed limits (and a lobbying effort that has the same influence and deep pockets as the American gun lobby), some speed regulations can be found on the Autobahns.  Many sections do indeed have permanent or dynamic speed limits ranging from 80 to 130 km/h (50-80 mph), particularly those with dangerous curves, in urban areas, near major interchanges, or with unusually constant heavy traffic.  In construction zones, the limit may be as low as 60 km/h (37 mph).  Also, some sections now feature nighttime and wet-weather speed restrictions, and trucks are always regulated (see table below).  That said, about two-thirds of the Autobahn network has no permanent speed limit, although there is always an advisory limit of 130 km/h (81 mph).  This recommendation is generally seen for what it is-- an attempt by the government to cover itself without having to upset millions of Porsche and BMW owners/voters.  However, if you exceed the advisory limit and are involved in an accident, you could be held responsible for some of the damages even if you are not at fault.  

MAXIMUM SPEED LIMITS (These are "default" limits; where posted, signs override these limits)

Vehicles that are limited to a lower speed limit will usually have a decal resembling a speed limit sign displayed on the back of a vehicle indicating the speed it is authorized to travel depending on its specific characteristics.  In some cases, those vehicles may be authorized to travel slower or faster than the general limit and will display the appropriate decal indicating such.

Over 3,200 km of Autobahn now feature dynamic speed limits which are adjusted to respond to traffic, weather, and road conditions.  These speed limits and conditions are indicated using a rather elaborate system of electronic signs (see below).

A movement by the environmentalist Green party to enact a national speed limit has not made great strides.  The Greens claim that the high speeds contribute to air pollution which has caused widespread Waldsterben, or forest destruction.  As a result, some Autobahns in forest areas have seen new limits imposed, but a national limit remains unlikely, as demonstrated during the coalition government negotiations in 1998.  In those talks between the then-new Federal Chancellor Gerhard Schroeder's Social Democrat party and the Greens, one of the final points to be resolved was the Greens' desire for a nationwide 100 km/h speed limit on the Autobahns.  In the end, a compromise was struck whereby energy taxes would be raised and local governments could reduce speed limits on city streets, but no national Autobahn speed limit would be implemented.  Subsequent discussions by various groups of a possible blanket limit have met with immediate and formidable political resistance.

A national speed limit of 100 km/h (60 mph) was enacted in November 1973 during the energy crisis. It was repealed less than four months later.

In 2008, the federal city-state of Bremen enacted a 120 km/h speed limit on all Autobahns in that state, the first and thus far only federal state to do so.  However, in practice, this only affected 6 km of Autobahn as the remainder of the 60 km of Autobahn in that state already had speed limits in place.

Accident rates
Despite the prevailing high speeds, the accident, injury and death rates on the Autobahn are remarkably low.  The Autobahn carries about a third of all Germany's traffic, but injury accidents on the Autobahn account for only 6% of such accidents nationwide and less than 12% of all traffic fatalities were the result of Autobahn crashes (2009).  In fact, the annual fatality rate (2.7 per billion km in 2009) is consistently lower than that of most other superhighway systems, including the US Interstates (4.5 in 2009).  Furthermore, a 2005 study by the German government found that Autobahn sections without speed limits had the same accident rate as those with speed limits.

Because of Germany's location in central Europe, traffic on the Autobahn is generally quite heavy.  In 2008, motorists logged a staggering 225.3 billion kilometers on the Autobahn, averaging almost 50,000 vehicles per day on any given segment.  As a result, traffic jams (Stau) occur frequently on the Autobahn, especially on Fridays, Sundays, holidays, and anytime after an accident or during bad weather or construction.  Regional traffic reports, with a variety of names including Verkehrsmeldungen, Verkehrsdienst, Verkehrsfunk, and Stauschau, are excellent and are provided on most radio stations.  Germany is divided into several traffic reporting regions (Verkehrsrundfunkbereich); signs along the road indicate the local radio stations carrying the traffic reports for the region you are in.  You will need to have a working knowledge of German to understand them, though. 

In addition to radio traffic reports, many sections of Autobahn are equipped with traffic monitoring systems and electronic signs (see below) to warn of downstream incidents or congestion and to provide a controlled reduction in the speed of traffic as it approaches the jam.  On sections without electronic signs, the Autobahn police (Autobahnpolizei) do an excellent job of warning of unexpected jams via portable roadside signs, signs mounted on police cars parked along the shoulder, or on banners draped from overpasses.  Traffic information is also available from several other resources including the websites of radio and TV stations, auto clubs, and government agencies, and increasingly through on-board telematics systems.

A couple of notes about traffic reports: sometimes the "traffic report" may include information that has nothing to do with traffic such as emergency alerts, police bulletins, etc.  Also, if you have a German rental car with a cassette or CD player, don't be surprised if your favorite tape or disc is interrupted by reports of a Stau somewhere-- German radio tuners continue to monitor the last-selected radio station even when a tape or CD is being played.  Radio stations broadcast a special tone at the start of traffic reports which causes the tuner to switch the audio from the tape or CD to the radio so that you can hear the information.  Traffic reports use one of several terms to describe varying levels of congestion: "Stau" usually means a colossal traffic jam where you'll probably get to know the people in the cars around you, "stockender Verkehr" indicates the only slightly more tolerable stacking or slow-and-go type traffic, while "dichter Verkehr" or "zähfliesender Verkehr" denotes the hardly-noteworthy heavy or sluggish but moving traffic.

As a stopgap measure to help improve traffic flow, traffic is now being permitted to use the emergency shoulder as a traffic lane during congested periods along some sections of Autobahn.  Lane control signals, signs, or other cars doing so indicate when this is permissible.

Autobahn maintenance and improvements don't escape the German penchant for obsessiveness.  As a result, construction zones (Baustelle) are frequent and widespread.  The standard protocol for large projects is a traffic shift-- the lanes for both directions are narrowed and crammed onto one side of the Autobahn so that the other side can be worked on in its entirety.  Such situations are well-marked with signs and speed limits are usually reduced greatly in these areas.

In the event that a segment of Autobahn must be closed due to an accident or other emergency, pre-posted provisional detours are ready to guide traffic around the closure.  As you exit, look for the U-numbered detour sign on the exit ramp-- this denotes the detour route for that exit.  Follow the same-numbered route over the secondary roads and you'll eventually arrive at the next downstream entrance ramp.  If that entrance is also closed, just follow the next sequential detour number to reach the next entrance after that.  However, there is one small gotcha-- odd numbers continue in one direction, even numbers in the opposite direction.  So if you're following an odd numbered route, be sure to follow the next sequential odd number (and, obviously the same goes for even-numbered routes.)  These routes also come in quite handy if your patience runs-out and you want to get around a Stau.

The Autobahn has an extensive system of service areas (Rasthof, Raststätte) generally spaced between 40 and 60 kilometers apart.  These usually feature a fuel station (Tankstelle), restaurant or snack bar, convenience store, telephones, and restrooms.  Many also feature hotels, showers, playgrounds, conference rooms, and chapels.  There are over 700 service areas in operation and they're open 24 hours a day.  A brochure with maps and charts showing the network of service areas and the facilities available at each can be obtained at any service area and is also available on the web (see links below).

Signs announcing the approach of a service area give the name of the service area, the distance to it, and one or more pictograms indicating the services available there:

Fuel	Restaurant	Snack bar	Hotel

Smaller parking areas, many equipped with restrooms (WC), are even more abundant along the Autobahn.  These are marked with signs like the one below.

The past couple of decades has seen the proliferation of service facilities (mainly fuel stations and fast-food restaurants) just off Autobahn exit ramps.  Especially increasing in popularity are truck stops (Autohof).  These generally offer facilities comparable to the service areas, but usually at considerably lower prices.  Most are now marked by special signs on the Autobahn like the one below.

In addition to marking lanes closed by accidents or construction, lane control signals are used in some areas to close lanes to help reduce congestion at interchanges.  For instance, if there is significantly heavier traffic merging from Autobahn 1 onto Autobahn 2, the right lane on Autobahn 2 will be closed to provide an unobstructed lane for the heavier traffic to merge into. 

When different speed limits are shown on a single gantry, the limit shown applies to the lane under the sign.  In the example below, the speed limit in the left lane would be 120 km/h, 100 km/h in the center lane, and 80 km/h in the right lane.

Over 1,700 km of Autobahn are part of dynamic alternate route systems.  These systems employ changeable guide signs which, when activated, display recommended alternate route guidance to help drivers avoid congestion.  Some areas employ "substitutive routing" where the destinations shown on the standard blue guide signs are changed using mechanical panels to re-route traffic onto different routes.  In other areas, "additive routing" is utilized.  In this case, the regular blue guide signs are static, but additional white signs with changeable panels and the big orange "alternate route" arrow symbol are used.  The arrow points in the recommended direction to follow along with the destination city, route number, or vehicle types (e.g. trucks) that the suggested alternate route applies to.  For instance, in the picture below, traffic headed to Deggendorf and the Munich airport is being advised to exit in 1200 meters and follow the A99 and A92.  Once you are on one of these alternate routes, continue to follow alternate route arrow signs until you have reached your destination or have returned to the original route.  Note that many times much of the alternate route is marked by permanent static signs, but a dynamic sign is used at the initial "decision point". 

Autobahn emergency phone

Roadside post with arrow pointing direction to nearest emergency phone

The emergency phone system was privatized a decade ago.  All calls go to a central call center in Hamburg.  In the event of an accident, dispatchers there will immediately connect the caller to the nearest police or emergency services office.  For breakdowns, the dispatcher will obtain the information necessary to send the appropriate service.  This may include the "Yellow Angels" of the ADAC or AvD auto club, a tow truck, or an insurance, dealership, or rental car repair service.  Roadside assistance is free, but you'll likely have to pay for parts.  If you need to be towed, there is no charge to remove the vehicle from the Autobahn, but you will have to pay for towing beyond that.  If you're driving a rental car, all services should be covered by the rental agency.  Depending on the time of day, volume of calls, and traffic conditions, response time for a breakdown may vary from a few minutes to possibly over an hour.

There are now two varieties of emergency phones in use.  On the older phones, you will find a cover with a handle.  Lift the cover all the way and wait for a dispatcher to answer.  The newer phones don't have a cover; instead, they have an external speaker/microphone area with two buttons that you can press to connect you to the appropriate dispatcher.  There is a yellow button with a wrench symbol for reporting a breakdown and a red button with a red cross to report an accident.  Press the appropriate button and wait for a reply.  In most cases, the location of the phone is transmitted automatically when your call is connected.  If not, you will need to give the dispatcher the kilometer location of the phone as indicated on a label on the inside of the cover or near the speaker and your direction of travel.  For an accident, report the number of vehicles involved and any injuries.  For a breakdown, be prepared to report the vehicle's license number, make and model, color, and your auto club, insurance company, or rental agency.  An English-speaking dispatcher is usually available.

After calling, return to your vehicle or the accident scene and wait for help.  For breakdowns, someone will arrive shortly to assist you.  In the event of an accident, a cavalry of emergency aid will descend on you.  Police, fire service, ambulances, and emergency doctors all respond to Autobahn crashes.  A medical evacuation helicopter is also always on standby.

Alternatively, you can contact the emergency call center via mobile phone at 0800 6683 663.

Old-style emergency phone

New-style emergency phone