One of France's longest-running city bus types, the PR100 and its derivatives can still be found all over the country. In its production life of over 25 years, the PR100 series has been facelifted twice but still managed to remain recognisably the same bus. 

The story of the PR100 dates back to the beginning of the 1970s. At this time, Berliet's major city bus type was the front-engined PCM, introduced in 1965. However it had become evident that the PCM was not selling as strongly as its major rival, Saviem's SC10. Berliet decided to replace the PCM with a model that was more in the mould of other continental single-deckers of the time. The new bus was christened the PR100 and went into production in 1972.

Mechanically, the PR100 couldn't have been more different from its predecessor. Where the PCM had had its engine at the front under the cab floor, the new PR100 had its engine in a far more conventional place under the floor in the rear overhang. This meant that there could no longer be a flat floor for the full length of the bus, as had been intended when the SC10 and PCM had been designed. However, since one-person operation was now the norm in most fleets and passengers were no longer required to board at the back, this was no longer considered to be a problem. The PR100's power was supplied (initially at least) by a V8 engine, either supplied by the British firm of Perkins or built by Berliet themselves. Perkins-powered buses are designated PR100PA, Berliet-engined buses being known as type PR100B.

The bodywork was built by Berliet themselves, and while the general layout of the bus was very European the designers managed to bring a distinctly Gallic style to the look of the new machine. Gone was the barrel-type windscreen that had featured on the SC10 and PCM – the new bus had a large, flat windscreen, curved at its lower edge, with distinctive deep quarterlight windows on either side. A heavily peaked front dome and substantial-looking front bumper finished off the front end. The overall look was very much a product of the 1970s, however it aged gracefully and remained in production without change for 12 years.

Four years after the introduction of the PR100, Berliet was sold by its owners, Citroën, to rivals Renault. Initially, Saviem and Berliet products continued to be marketed separately, so the buses continued to be badged as Berliets. However, the new owners did make a major mechanical change to the bus – the V8 engines that powered early PR100s were not as reliable as had been hoped and Renault re-engineered the bus in 1977 to take the six-cylinder MI-series engine. Variants of this engine have powered the bus ever since. The most common engine option for the PR100 was the non-turbocharged MI engine (buses powered by this are known as PR100MI), however for some overseas markets where more power was required a turbocharged version (the PR100MIPS) was offered. Some French operators also purchased this, with Marseille in particular building up a large fleet.

By the end of 1980, Renault had merged Berliet and Saviem into a new subsidiary, Renault Véhicules Industriels, so the familiar diamond logo replaced the Berliet name on the front of new PR100s.

By the late 1970s interest in articulated buses was growing in France. In 1978, Mercedes and Heuliez together launched the articulated O305G onto the French market, and other fleets such as those in Caen and Nantes bought German-built Setra SG180 buses. The country's major bus and coach builder was rather slow off the mark in producing an articulated bus, and initially competed in this market by selling MAN SG220 artics built in Germany and finished off by bodybuilder Gangloff in France. In order to make these buses politically acceptable in France, they were badged as Saviems (later Renaults), despite their connection with the Saviem factory being tenuous to say the least! In the meantime, Renault busied itself developing an articulated version of the PR100, which emerged in prototype form in 1979. The PR180 has its engine in the rear section, however this drives both the axle under the rear section and the second axle of the front section. Production of the PR180 started around the beginning of 1981, so all the production buses carry Renault badges. Once the PR180 began to come on stream Renault ceased importing the MAN artics.

Since 1993 Safra has rebuilt numerous old PR100s and PR180s, of both mark 1 and mark 2 versions, using their own design of front end (also fitted to the PR112 and PR118 models). More details of the refurbishment can be found here. 

Around 1200 PR100PAs were produced, about 300 PR100Bs and about 1730 PR100MIs (930 with Berliet badges, 800 with Renault). PR100MIPSs are less common, some 500 having been built (although most of these were for export). Just over 350 mark I PR180s were produced.

Mark I PR100s and PR180s are now becoming scarce across France, with the early V8-powered PR100s now virtually extinct. Due to the expense and complexity of articulated buses (and the limited mileages they may cover performing peak-hour work and schools journeys), PR180s tend to last a bit longer in main operator service than their rigid counterparts. However, where buses are intended to remain in service for some time they are often treated to a refurbishment with a Safra front end, so unadulterated PR180s are not very common.

Sadly, no mass-produced models have yet been made of any members of the PR100 range.