A countdown clock for the end of an over and a standard ball in Test cricket are among changes that have been suggested by a group of leading figures in the sport.
The MCC World Cricket committee has proposed playing the World Test Championship, which begins with this year's Ashes, with a standardised ball.
The committee is an independent panel that can propose changes to the laws.
Three different brands of red ball are currently used in Tests.
A Dukes ball is used for Tests in England and West Indies, while the SG ball is used in India. All other countries play the longer format with a Kookaburra ball.
The committee - which includes ex-Australia leg-spinner Shane Warne and former England captain Mike Gatting - said the "balance between bat and ball is crucial".
They also suggested measures to speed up play in Tests, including:
*Free hit to follow a no-ball in Test cricket
*A timer or countdown clock to count down from 45 seconds from the call of "over"
*If either side is not ready when the clock reaches zero, they would receive a warning
*Further infringements in that innings would result in five penalty runs being awarded to the opposition
*A timer when a wicket falls to ensure batsmen and fielders are in position in time.
Free hits after a no-ball are already used in limited-overs formats.
Ninety overs should be bowled in a full day's play, with an extra 30 minutes available if teams need to make up time.
A survey conducted by the MCC said 25% of fans from England, Australia, New Zealand and South Africa said slow over rates put them off attending Tests.