F1開賽前為什麼推上賽道？

F1開賽為什麼都是工作人員推著上去的？不能直接開上去么？

38) STARTING PROCEDURE
38.1 30 minutes before the start of the formation lap the pit exit will be opened and cars will be
permitted to leave the pit lane to cover a reconnaissance lap. At the end of this lap they will
stop on the grid in starting order with their engines stopped.
Should they wish to cover more than one reconnaissance lap, this must be done by driving
down the pit lane at greatly reduced speed between each of the laps.
All drivers going to the pit exit at this time must do so at a constant speed and with constant
throttle. This applies over the whole of the pit lane whether a driver is going to the pit exit
from his garage or travelling through the pit lane between reconnaissance laps.
Any car which does not complete a reconnaissance lap and reach the grid under its own
power will not be permitted to start the race from the grid.
38.2 17 minutes before the start of the formation lap, a warning signal will be given indicating that
the end of the pit lane will be closed in two minutes.
15 minutes before the start of the formation lap the end of the pit lane will be closed and a
second warning signal will be given. Any car which is still in the pit lane can start from the end
of the pit lane provided it got there under its own power. If more than one car is affected they
must line up in the order in which they qualified. However, any car reaching the end of the pit
lane after the five minute signal must start behind any car already at the pit exit.
All such cars may then join the race once the whole field has passed the end of the pit lane for
the first time after the start.
38.3 The approach of the start will be announced by signals shown ten minutes, five minutes, three
minutes, one minute and fifteen seconds before the start of the formation lap, each of which
will be accompanied by an audible warning.
When the ten minute signal is shown, everybody except drivers, officials and team technical
staff must leave the grid.
38.4 When the three minute signal is shown all cars on the grid must have their wheels fitted, after
this signal wheels may only be removed in the pit lane, or on the grid during a race
suspension.
A penalty under Article 16.3(c) will be imposed on any driver whose car did not have all its
wheels fully fitted at the three minute signal.
38.5 When the one minute signal is shown, engines should be started and all team personnel must
leave the grid by the time the 15 second signal is given taking all equipment with them. If any
driver needs assistance after the 15 second signal he must raise his arm and, when the
remainder of the cars able to do so have left the grid, marshals will be instructed to push the
car into the pit lane. In this case, marshals with yellow flags will stand beside any car (or cars)
concerned to warn drivers behind.
……

大意就是：暖胎圈前30分鐘，車輛自行駛離維修區做巡場圈，巡場圈結束後，停在發車格指定位置（如果被罰維修區起跑就停維修區）。並且，關閉引擎。
隨後根據發車燈號和賽場廣播提示，車組人員可以對停在發車格上的車輛執行技術調整工作。
還剩三分鐘時，車輛輪胎必須就位。還剩一分鐘時，需要重新給車輛點火並且在還剩15秒的燈號亮起前確保全部技師撤離發車區（否則會被罰）。然後在安全車帶領下跑暖胎圈，然後正賽起步。