IndyCar reveals new testing restrictions for 2017 season

Next year the series will hold four open tests, with teams permitted one extra test day between April 11-Septempber 17.

The new restrictions will come into place on October 3 this year, when a window running until April 6 2017 will begin, with teams allowed three test days during that period.

"We collaborated with all of our teams on the 2017 testing regulations with the goal of minimising the amount of in-season testing," said Jay Frye, IndyCar president of competition and operations.

"The majority of testing will take place at a series of open tests, which have been strategically routed to coincide with our race schedule.

"As we finalised our regulations, the focus was on making our test schedule more efficient and minimising the overall demands on the crews during the year.

"We're confident that this is a positive step forward for the series."

The 2017 open tests will take place at Phoenix on February 10-11; Barber Motorsports Park on March 21; Gateway on May 2 and Sonoma on September 14th - the same week as the season finale.

Teams may earn additional test days by running a rookie driver (up to four days) for the season, a current Indy Lights driver (one day) or operating an Indy Lights team under the same ownership as the IndyCar team (one day).

New teams entering the series would be allowed up to four additional test days.

Tyre testing will take place at the request of official supplier Firestone.

Any tyre test is limited to two days, either in-season or off-season, with no more than two teams participating.

All teams are permitted to have one car conduct team testing during an in-season tyre test.

Engine testing for Chevrolet and Honda is limited to two days for each manufacturer in the off-season window.

Teams were allowed eight private test days in 2016, with the bonus days for running an Indy Lights team or driver set at one apiece.