Uber drivers may have to take an advanced driving test in order to work, according to proposals being worked on by Transport for London.
Plans are also being drawn up to remove their Congestion Charge exemption as TfL responds to "changes in the private hire industry".
The plans are revealed in TfL's new policy statement on private hire services in the capital, in response to challenges "including how to apply existing licensing legislation, managing the impact of more vehicles moving around the city".
The document avoided naming Uber, despite TfL declining to renew its licence resulting in a lengthy appeals process and an uncertain future for its 40,000 drivers and 3.5 million users in London.
New rules being considered by TfL for private hire operators include improved reporting of offences, data sharing with TfL and even allowing customers to chose who they share a ride with.
TfL has already cracked down on private hire operators and drivers, having quadrupled the number of compliance officers on the streets, to more than 300.
Drivers are now required to complete a formal English language requirement and operators must provide booking confirmations to passengers before the journey.
The new policy document highlights safety, accessibility and drivers' conditions as major areas of concern that require an improvement in standards.
It also highlights the environmental impact of private hire vehicles, citing the mayor's aim to have 80% of journeys made by foot, cycling or public transport in London by 2041.
In order to achieve this, traffic would need to fall by at least 10-15% over the next 25 years, while London's population is forecast to grow by more than 2 million over the same time period.
"Reducing people’s dependence on the private car is central to the aims of the strategy as is making more efficient use of limited street space available in London," says the report.
The TfL report acknowledges the current problems, saying "public transport services are becoming more crowded, congestion has been increasing and London faces significant challenges around worsening air quality and public health."
The report highlights the role ride sharing services could have on reducing car ownership in inner London, as well as "having the potential to play an important role in supporting mode shift away from the private car, particularly in outer London".
Any major changes to TfL policy on private hire is likely to involve a public consultation.
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