Traffic that grinds to a halt and then restarts for no apparent reason is one of the biggest causes of frustration for drivers. Researchers at Bristol University have showed that ‘phantom jams’ (or ‘jamitons’) are caused by 'shock wave' effects with some similarities to fluid dynamics, which have been described as ‘kinematic waves’. Basically, one car stops or brakes heavily. The following car does the same and so on. By the time this has rippled back, the car at the front has moved off. But the time it takes for each car thereafter to start off again is slower than the time it takes for more cars to join the back of the ever-growing queue. Given the right conditions, a touch to the brake by a single driver may be enough to start a wave of congestion that then travels slowly backwards down the motorway, typically at 15-20 km/h.
The annual costs of congestion in terms of time and fuel are estimated at $100 billion in the US and £8 billion in the UK and are predicted to double within 15 years.
The average speed of traffic in London today is 8mph. The average speed of a London horse-drawn carriage in 1900 was also 8mph.
You can't be a nice guy and solve traffic.
In the 1890s the key environmental concern was horse manure. London had 11,000 cabs and several thousand buses. Each used 12 horses per day, totalling more than 50,000 horses working in public transport alone. Each horse produces 15-35 pounds of manure per day; New York had 2.5 million pounds per day to shift, and in 1894. The Times predicted that every street in London would be 9ft deep in dung within 50 years.
‘Crossing sweepers’ were employed to clear paths through the dung, which was either sludge in wet weather or a fine powder which blew about in the dry. The piles of manure produced huge numbers of flies, which spread typhoid fever and other diseases; one estimate is that three billion flies hatched in horse manure per day in US cities in 1900, and in NY, 20,000 deaths per year were blamed on manure.
In 1898 the first international urban planning conference convened in New York to discuss the issue. It was abandoned after three days, instead of the scheduled ten, because none of the delegates could see any solution – but within a few years the problem had entirely disappeared. Electric trams and then cars and motor buses led to a rapid collapse in the horse population; in 1912, New York, London, and Paris traffic counts all showed more cars than horses for the first time, and most cities experienced their first motor traffic jams in 1914.
There are no traffic lights in Bhutan.
In 2010, a traffic jam in China which was originally caused by roadworks and high demand and exacerbated by broken down vehicles and people leaving their cars, stretched for more than 100km on a major national highway leading from Beijing. Drivers were managing as little as one kilometre per day. They passed the time with games of chess and cards by the roadside.
Traffic jams are so bad in China there’s now a service that allows someone else to sit in a traffic jam for you. You call the company and motorcycle arrives with two people. One stays with your car and the other puts you on the back of the bike and blasts off through the jam.
In 2009, two feuding mayors in France declared the same road one-way: in different directions.
There are no traffic jams along the extra mile.
In 2010, twice as many Britons died in accidents in their own homes as in traffic accidents.