But Italian authorities have said they don't know exactly how many cars were on the collapsed section of the bridge or the number of people that were in them.
Italian President Sergio Mattarella and Prime Minister Giuseppe Conte are due to preside over the state funeral.
The collapse of the Morandi Road Bridge in Genoa on Tuesday, which killed 38 people, was both an engineering and a human tragedy.
Nunzia Esposito, whose 26-year-old son, Gerardo, died, said the Italian state was responsible for the collapse, adding: "The parade of politicians has been shameful".
Others opted for private funerals, including one a day earlier for four friends, young men in their 20s, from the southern town of Torre del Greco.
Antonio Brencich, a University of Genoa lecturer, said there were "eyewitness accounts and videos that go in this direction".
The names of the dead were placed on each coffin before the altar.
Genoa's Catholic archbishop Cardinal Angelo Bagnasco said the city has "had its heart torn out" as he led the funeral service.
This includes a fund for the "immediate requirements" of the victims' families.
Mauro Brezzo, chaplain of Genoa's San Martino hospital, said: "Many do not want to take part in a showcase, and I understand them".
Genoa said on Twitter that club president Enrico Preziosi had requested the postponement "following the state of mourning in the whole city of Genoa".
The government has also lashed out at Brussels, claiming that strict spending rules imposed by the European Union had prevented Italy from investing in new infrastructure over the years.
Italy's president has comforted families of numerous Genoa bridge collapse victims.
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What is the government doing?Prime Minister Conte sent the company a "letter of complaint" on Friday to begin that process, according to reports.
"Today the government. has formally sent to Autostrade per l'Italia the letter of complaint which launches the process for revoking the concession", he said in a statement.
Autostrade has 15 days to respond to the letter.
The company has insisted that it more than fulfilled its duties.
Autostrade has said it monitored the bridge on a quarterly basis as required by law and that it had carried out additional checks by hiring external experts.
Shares in the operator's parent, Milan-listed global Atlantia, fell by as much as 25 percent at one point as investors spooked by threats of government retaliation dumped the stock.
It has raised serious questions about the bridge's construction, the way it was maintained and the safety of Italian infrastructure.
Victims of the Morandi Bridge disaster lie in coffins at the Fiera di Genova exhibition centre.
The bridge is a main road in and out of Genoa, linking it to the A10 motorway and the road to France.
But the bridge collapse is the latest symptom of Italy's woeful infrastructure, a sector where big projects have provided rich pickings for the Camorra of Naples, the 'Ndrangheta of Calabria and Cosa Nostra in Sicily.
The service came as firefighters still searching for five missing people discovered a vehicle with human remains inside.
But rescuers have not given up hope of finding someone alive.
Shortly after the official ceremony, Autostrade announced it would make 500 million euros ($570 million) available to help those affected by the tragedy and rebuild the partially collapsed bridge.