The referendum launched by opponents to the law was defeated on Sunday by around 56 percent of citizens who cast ballots nationally, with a majority of voters in 18 of the country’s 26 cantons saying yes to the changes.
Supporters of the legislation argue that it ends the “absurdity” over what can be sold in a service station shop.
From 1 to 5am and on Sundays such shops are not allowed to sell anything other than coffee and prepared food to customers, in addition to fuel.
Backers of the change used the national sausage as a symbol of what was at stake.
Under the previous law, it was OK to sell a prepared cervelat (sausage) to a customer during the early morning hours and on Sundays, but it was not possible to sell an uncooked sausage.
The new legislation limits what can be sold at service stations shops to the needs of travellers, essentially food, hygiene products, magazines and newspapers.
Opponents of the changes said the relaxed regulations would open the door to rampant liberalization of opening hours for shops generally in the country.
Past efforts to change restrictive shopping laws have met with little success in Switzerland, where most shops close on Sundays and late-night shopping is not allowed outside of train stations and airports.
Unions representing shop workers are opposed to the longer hours, arguing they are not good for employees with families.
The change in the regulations governing petrol station shops will actually only affect 24 stations located along motorways, the union group Schweizerische Gewerkschaftsbund (SGB) says.