As he tours the east and north of his country this week, Emmanuel Macron might consider the hundreds of useless structures which span motorways all over France.
They are elaborate monuments to a €1 billion fiasco and act of political cowardice which occurred in another political age – five years ago.
Demonstrations and violence by red-hatted hordes in 2013 persuaded President François Hollande to scrap plans to impose an ecological tax on trucks.
Journeys were to have been recorded by cameras and sensors on motorway gantries. The gantries still exist but have never been used.
(Cameras on a defunct eco tax gantry over a motorway in France. AFP)
(Protesters separated from one of the eco tax "gates" by barriers and riot police in 2013. AFP)
On 17 November, President Macron faces a potentially even more explosive rebellion, not just by truck drivers and their allies but by tens of thousands of rural and suburban motorists.
They are being exhorted – despite concessions made by the President yesterday – to block roads all over France on Saturday week to protest against a rapid rise in pump prices.
The uniform of this revolt is not a red woollen hat but the yellow hi-vis jacket which French drivers carry in their vehicles by law. A “gilet jaune” draped over the dashboard of a car has become the symbol of a viral protest which threatens to cripple an already unpopular President.
(The "yellow jackets" protesting fuels prices in a stand off with French riot police. AFP)
The revolt is primarily about a steep rise in pump prices, especially for diesel (which still powers over 60 per cent of French cars). In the last 12 months, the typical French forecourt price for “sans plomb 95” has risen from €1.36 a litre to over €1.60. The price of diesel has risen from €1.24 to over €1.50.
Most of that rise is due to a leap in the wholesale price of oil from $60 for a barrel of Brent crude to $85. But the anger of the “yellow jackets” is not directed against Opec, for reducing production, or against Donald Trump, for blocking exports from Iran. The anger is focused on a Hollande-era environmental policy, extended by Macron, to drive up taxes on car fuel and especially on diesel (gazole).
“Gazole” was undertaxed for decades in France in the mistaken belief that it polluted less than petrol. The gap is now – rightly – being closed. Taxes on diesel went up by 8 centimes last January and taxes on petrol by 4 centimes. The diesel tax will go up by another 6.5 centimes in the New Year. and petrol by 2.9 centimes.
But the hi-vis rebellion is not just fuelled by pump prices or by environmental policy. Motorists in rural and outer-suburban France were already furious with Macron for forging ahead in July with a reduction in the speed limit on most two-lane roads from 90 kph to 80 kph.
(Bikers protest against 80km/h speed limit. AFP)
Both measures – the fuel price rises and the 80 kph limit – are seen in rural and “peri-urban” France as an attack by a “metropolitan President of the rich” on the countryside and the poor.
Outside the cities, protesters say, a car is not an occasional instrument of pleasure. It is a necessity. We are being doubly and trebly punished by speeding fines, oil prices and fuel taxes. This is, intentionally or not, an assault on our way of life.
The yellow jacket protests are all the more menacing for being spontaneous and seemingly apolitical, spread on social media by a loose alliance of blogs and web-sites. Attempts by the right and far right to exploit the pump rage are being systematically rebuffed, according to the leaders of the revolt.
How long this will remain true is open to question. The red bonnet rebellion began in Brittany as a protest against truck taxes and rapidly spread to become an anti-green, anti-urban, anti-“elitist” revolt against a centre-left government. François Hollande, scenting danger, caved in.
Emmanuel Macron also scents danger. This week he hijacked an idea already introduced by the Hauts de France region. There will be a €20 a month tax “refund” for anyone who drives more than 30 kilometres to work, so long as they earn less than twice the minimum wage and no public transport is available.
That is unlikely to quell the protest. The yellow-jackets insist that Macron must abandon next Januarys tax rises.
He has refused. The fuel tax rises, he says, are part of an inevitable movement away from fossil fuels and especially away from high-polluting diesel cars.
Macron is right. He is also right about the 80 kph limit. France has over 3,500 road deaths a year, more than double the number in Britain with the same population of people and cars. Most of the deaths occur on two lane roads.
But the protesters also have a right to be aggrieved. The coincidence of oil price rises and higher forecourt taxes has been disastrous for many rural or suburban families.
A fall in crude oil prices might ease the tension for a while but this dispute foreshadows other crises to come: Motorists v environmentalists; Cities v the countryside and outer suburbs. The fault-lines follow closely the cultural divides revealed in last years presidential election and also seen in Britain and the United States.
President Macron, already struggling in the polls, is about to face a high-visibility test of his courage and nerve.
John Lichfield is the former France correspondent and foreign editor for the Independent newspaper. You can follow him on Twitter @john_lichfield