A shock survey revealed up to 500,000 ticket holders have yet to consider the extra time needed or alternative routes to use as a result of road restrictions and tight security in and around Games sites.
Road chiefs and organisers of Glasgow 2014 are working to keep traffic moving through the city amid fears of gridlock conditions as more than one million spectators descend on Glasgow for Scotland's biggest ever sports event.
But research commissioned by Games officials reveals that up to half of the spectators have yet to work out how they will get there. Organisers are pleased that 50% of them have finalised travel arrangements but have warned the others that forward planning is key to keep Glasgow moving.
Planning ahead will also help residents and workers to get around more easily, says Michael Renshaw, the director of transport and logistics at Glasgow 2014.
He said: "Many of the spectators know the city well but venues and much of the transport network will operate differently from what people are familiar with.
"All venues have different travel options and there is no general parking available. Spectators can help make their journeys as easy as possible by planning ahead and visiting the Glasgow 2014 website to view and use all the available travel resources to plan for a great day out.
"Glasgow 2014 is a walking, cycling and public transport Games. Many of the venues are within walking distance of the city centre and there are a number of venues where walking times may be slightly longer.
"But going on foot may still be the quickest and most relaxing way to get around, plus it means avoiding inevitable queues at transport hubs particularly after the end of events.
"Cycling will also be one of the quickest ways to get about the city and there are new Glasgow City Council bikes available for hire at 31 locations across the city including six Commonwealth venues. Glasgow 2014 has also provided more than 1000 bike parking spaces across all venues.
"We have been working with partners including Transport Scotland and Glasgow City Council to make transport run as smoothly as possible and give travel advice."
The findings come 24 hours before the opening ceremony and when spectators can use their Games tickets to access free public transport within a Games travel zone which takes in Glasgow, Clydebank, Bishopbriggs, Rutherglen, Cambuslang, Burnside, Clarkston and Giffnock
There are also arrange-ments for shuttle bus services to Hampden Park, Ibrox Stadium, Cathkin Braes, Celtic Park and Strathclyde Country Park, as well as a park-and-ride service for selected venues.