The motor industry has been accused of trying to ‘bury’ a report that allegedly reveals American cars are substantially less safe than those in Europe.

The study was commissioned by the motor industries in the US and Europe in an attempt to show that existing US and European Union safety standards are broadly similar.

The aim was to bolster a controversial Transatlantic Trade and Investment Partnership (TTIP) deal that will allow vehicles approved by US regulators to be sold in Europe and vice versa.

But the research actually showed that US models are much less safe in the event of a front-side collision, according to safety campaigners.

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Collision tests were carried out on both European and US vehicles after the research was commissioned by the Alliance of Automobile Manufacturers

They said the research indicated that the TTIP negotiators could be potentially putting lives at risk.

The study, leaked to the Independent, was commissioned in May last year by the Alliance of Automobile Manufacturers.

Its members include BMW, Daimler, FIAT, Jaguar Land Rover, PSA Peugeot Citroën, Renault, Toyota, Volkswagen and Volvo - as well as Chrysler Ford and General Motors Company.

The study was carried out by independent experts at the University of Michigan Transportation Research Institute and the Safer Transportation Research Centre at Chalmers University of Technology in Gothenburg, Sweden.

The report's co-author Andras Balint - who is a traffic safety analyst at the Swedish research centre - told the Independent: 'The results of our study indicate that there is currently a risk difference with respect to the risk of injury given a crash between EU specification cars and US models.

'Therefore, based on these results, immediate recognition of US vehicles in the EU could potentially result in a greater number of fatalities or serious injuries in road traffic. The potential impact is difficult to quantify because it depends on a number of other parameters.'

The researchers found that European crash-testing regulations are far higher than those in the United States

Despite commissioning the report, auto manufacturers have not officially published the findings.

When the research plan was announced in May, the Alliance noted: ‘The study is evaluating whether motor vehicles manufactured in compliance with either the EU or US regulatory requirements provide essentially equivalent real-world safety performance when driven on European roadways or on US roadways.’

It added: ‘EU-US auto-related trade currently accounts for 10per cent of total trade between the two regions. Together, the EU and the US account for 32per cent of global auto production and 35per cent of global auto sales. Under a TTIP, the two regions would represent the largest share of auto production and sales ever covered by a single trade agreement.’

Organisers ‘believe that the benefits of any ambitious agreement can only be reached if sufficient regulatory convergence is achieved.’

Antonio Avenoso of the European Transport Safety Council said: 'This study shows that EU and US trade negotiators would potentially be putting lives in danger by allowing vehicles approved in the US to be sold today in Europe and vice-versa.