Ca. 1877 he proposed a now widely used system of preferred numbers known as Renard numbers that was later reportedly published in an 1886 instruction for captive balloon troops, named after him in the 1920s and finally became international standardISO 3. It helped the French army to reduce the number of different balloon ropes kept on inventory from 425 to 17.
Colonel Renard invented the Renard Road Train first developed by Darracq [and Company London|Darracq] and displayed by them in 1903 later developed in England by Daimler. The leading motor unit having generated the power transmits it by a continuous shaft united between the carriages by a universal joint to the driving wheels of each carriage. These, each carriage being six-wheeled, are the central pair and are shod with iron, the resulting road-shock being taken by the springs and rubber tyres on the other wheels. Each vehicle is steered by its predecessor through a series of rods and linkages and when a Renard train rounds a corner each vehicle follows precisely in the track of its predecessor. They were powered by a 16.1 litre Daimler engine and the last carriage always cut the corner