With an annual average of more than 9,000 vehicles / day, including 900 heavy goods vehicles in transit between the coast and the Tarn, crossing Saint-Pons-de-Thomières is far from easy. Not to mention the essential delivery vehicles at the origin of many traffic jams, the width of the road is insufficient and the trucks must pass each other at walking pace. A deviation project was mentioned in the early 1970s, but faced with an outcry from traders fearing future economic isolation, it was quickly abandoned. The problem is far from new. It even dates back to the Middle Ages, at a time when traffic was through small alleys: Barry, Empéry, Lempinet and Place du Foiralet coming from Narbonne; rue Mazelières and rue du Marché then le Foirailet in the direction of Béziers-Castres. A real headache for the passage of cumbersome carts more and more numerous with the development of the cloth industry. In 1770, the rectilinear opening of the current Grand-Rue was decided. The site is colossal. Buildings are razed, and the ruins of the old monastery serve as embankments. As an extension, the creations of the avenue de la Gare and the route de Castres become obvious. The result is breathtaking and completely changes the economic life of the city. It was without counting, a few decades later, with the arrival and development of motor vehicles. Today the problem remains unresolved and is not going to improve with the Castres-Toulouse motorway project.