The average speed was  over about . On 6 June 1929, she drove a Bentley 4½ Litre at Montlhéry for 24 hours, to capture the world record for single-handed driving, averaging over .
The average speed was substantially higher than about . On 6 June 1929, she drove a Bentley 4½ Litre at Montlhéry for 24 hours, setting a new world record for solo driving by maintaining an exceptionally high pace.