Excess in case of negligence in the employment contract

Hello, I have been working as a courier driver in part-time for a few days and I want to sign the following item on the deductible in the employment contract: “In the case of vehicles damaged by negligence up to 300 euros, with external damage up to 500 euros deductible.” I have read that at least slight negligence should be excluded. In the case of gross and medium negligence, a deductible is common, right?