The chicanes, however, proved to be a makeshift solution and were responsible for numerous accidents and collisione, although not serious. And then, just as the cars had done, motorcycles too, at the end of the seventies, adopted large tyres with high adherence-coefficient compounds, and later with smooth-treads which, as they let riders lean over further, improved speed in the curves while considerably increasing the risk of falling and hence the number of accidents.
But the motorcycles continued to use the road track without chicanes and, in the first half of 1973, there were two serious accidents on the "Grande" curve. The first happened in the Grand Prix of Nations; shortly after the start of the 250 class Renzo Pasolini had a piston seizure which caused many to fall and in which Pasolini himself and the Finnish rider Jarno Saarinen lost their lives. Forty days later, in a juniores race the "gentlemen " riders Chionio, Galtrucco and Colombini fell and were fatally injured at the samepoint.
From then until 1981, the motorcycle Grand Prix was transfered to another circuit and bikes raced at Monza only on the junior track for minor championships. In this sport, too, extremely high speeds were achieved with Pasolini exceeding a lap average of 200 Km/h with a 350 cc a few bours before his fatal accident.
Following the serious situation created for cars, too, by the repeated, if not serious, accidents, which showed the ineffectiveness of the chicanes, in the three following years important work was undertaken to replace them with three layout changes or variants to slow down the track. In 1974 the chicane of the "Vialone" was completely revised, replacing the tight initial curve with a longer one and modifying the subsequent layout; on the continuation of the approaching straight a broad run-off area was created with a sand layer and catch fences. In 1976, to replace the chicane located on the grandstand straight, a variant was created in the section of the same straight after the beginning of the north curve of the speed track, consisting of a succession of two left curves alternating with two right curves with radius and angle such as to reduce speed in that section to about 100 Km/h at the inlet and 120 Km/h at the end. Top speed on the approaching straight of the "Grande" curve was thus reduced from over 300 Km/h to about 180 Km/h. At the same time, another variant was built at approximately 300 metres from the entrance to the first Lesmo curve, consisting of a left curve followed by a right curve and forcing reduction of top speed in the following straight from 280 Km/h to 180 Km/h.
These two variants were also given adequate runoff areas with sand layers and catch fences. The three variants, which brought the length of the road track to 5,800 metres, considerably reduced practicable speed.
Ronnie Peterson on a March won the Italian Grand Prix that year at 199.749 Km/h and recorded a fastest lap of 206.120 Km/h, a speed improved by Mario Andretti with a Lotus in 1977 (210.696 k m/h) and 1978 (212.562 Km/h).
The sporting activity in this period consisted mainly in car races at each level. For the main category, i.e. the Formula One Italian Grand Prix, Lotus won three times in a row with Fittipaldi in 1972 and with Peterson in 1973 and 1974; the victory then went to Ferrari with Regazzoni (1975), to March with Peterson (1976), again to Lotus with Andretti (1977), and to Brabham-Alfa with Lauda (1978). During this last Grand Prix, a terrible accident occured a few hundred metres after the starting line: Ronnie Peterson, taken to the hospital, died the next day, while Vittorio Brambilla recovered after several months at the hospital. The "Monza 1000-Km " was won by Ferrari in 1972 and 1973; thereafter, the Maranello team retired ,f'rom the Sports Prototypes Championship; in the following years, until 1978, the victory went three times to Alfa Romeo 33c and twice to Porsche.
At that time, in its various configurations - road track 5,800 metres-long, junior track 2,405 metres-long and, more rarely, speed track 4,250 metres-long - the circuit was used for various other types of motor sport events, among others the Agip Cadet Trophy, regularity competitions, dragster races, gimkanes, driving schools, but also non-motor sports such as cycling and running, roller skating, roller skying, and so on.
Other motor sports were practiced off the track, including motorcycle trials and automobile rallies, as well as various non-motor activities such as plant, animal, flower and foodstuff shows, matches and exhibitions of basketball, American football, boxing, judo, table tennis, artistic skating and gymnastics.
Italian and international races were held on the special model track.