Following a series of Michelin Fill Up With Air roadshows, the number of employees at BNP Paribas Group vehicle rental company Arval driving their cars on correctly inflated tyres has increased significantly. Over the past four years the events, run in conjunction with Michelin, have seen an improvement of 38 per cent, the tyre manufacturer says. Michelin staff checked the tyre pressures and tread depths of 151 Arval employee vehicles at the 2012 event, and more than two thirds of tyres tested were at the correct pressure or less than seven psi under-inflated.