You can compare the German speed limit to weapon ownership in US. Any party suggesting introduction of a general speed limit would conduct political suicide and face serious debates with the automobile lobby and voters (most workplaces here come from this branch). Most rational arguments points towards a speed limit (less traffic jam/noise, environmental pollution...), but similar to US weapon industry, there are to many automobile fanatics in all political parties (either green, liberal, democrats, conservative). You can only lose voters with this topic.
The historical circumstances are simply that a lot of automobile inventions were made in Germany, the car is a status symbol for many here.
When the introduction of a national speed limit for Germany's Autobahns (motorways and highways) was discussed in the 1980s, automobile associations of all kinds demanded the "Freedom of the roads for free citizens" – with at least some success back then. And even today, Germany still does not have a general speed limit. Although a maximum speed of 130 km/h is recommended, where no road sign expressly indicates this speed limit, drivers can decide for themselves how fast they would like to travel. If you should pick up a few angry comments about "Points in Flensburg" during a conversation, you can be sure that those involved are talking about the Kraftfahrt-Bundesamt (Federal Motor Transport Authority). Some 7.1 million car drivers are currently listed there. All of them ignored the signs and were caught driving too fast. The quicker they were travelling, the higher the fine and the number of points they collected. Travelling in your own car
Germany is seen as a country of car enthusiasts. No wonder then that this is where the first motor vehicle was invented. Today, the automotive industry is one of the country's largest employers. There is practically no other item that Germans would spend as much money on as a car. For students, having their own car is generally a luxury. The prices for petrol and diesel are higher than in other European countries and the required third-party insurance (Haftpflichtversicherung) also costs a lot of money. And still, many afford themselves the luxury of a car of their own.
The German "Economic Miracle" of the Fifties and Sixties were boom times for the car and road building industry. It was not until the world oil crisis of the early Seventies that the country's politicians were forced to contemplate the idea of speed restrictions on Autobhans. The then West German government reacted by imposing a ban on Sunday driving and introducing a 100kph speed limit for the duration of the crisis.