A quarter (25%) of those who admitted to throwing rubbish said they had thrown organic matter outside, such as fruit skin, pips or stones; while 14% admitted throwing cigarette butts and chewing gum.
Just 6% admitted to throwing items such as paper, tissues or food packaging, according to the poll by Ipsos for motorway company Vinci Autoroutes.
The results come ahead of the busiest driving weekend of the summer, as July holidaymakers (“Juliettistes”) “crossover” with August holidaymakers (Aoûtiens) between today (August 3) and Sunday (August 5).
Saturday has been classed as “black” alert in the departure direction - driving away from Paris and large towns - by national traffic forecaster Bison Futé. Black is the highest alert level possible, meaning “extremely difficult”.
Saturday is the only day of the summer season to be classed as black, with heavier traffic than normal expected due to the crossover between months.
Return traffic on Saturday has been classed as “orange - difficult”.
Today (Friday August 3) has been classed as on orange alert in the departure direction, although traffic is still looking clear (“green - normal traffic”) for the return.
Sunday has been classed a mixture of orange and green, depending on location.
To avoid the worst of the traffic, drivers are warned to leave as early or late as possible, and only drive in the small hours of the morning on Saturday only, or choose Sunday as your travel day instead.
She said that if possible, drivers and families should avoid travelling during the hours of midday and 16h00, and avoid being in hot cars at the peak of the day.
Temperatures have hit 40°C in parts of the country in the past few days, with the heatwave expected to continue until next week.
Ms Buzyn reminded drivers: "It is imperative to drive earlier in the morning or late in the evening, avoid periods of extreme heat, protect children. Take enough water in the cars, stop regularly."
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