Pages 213 and 214 of the book "Final Disclosure" by David Belin tells us:
"However, when Oswald was apprehended , he had a bus transfer. Shortly after the assassination, he boarded a bus, and when the bus stalled in traffic, he left it and hailed a cab. As Oswald left the bus, he asked for a transfer.
Why did he ask for the transfer? Was there some nearby bus-transfer point toward which Oswald was walking when he was stopped by Tippit? There was.
Evidence is circumstantial, but it is likely Oswald was fleeing to Mexico City when he encountered Tippit. While in the marines, Oswald once told a buddy, Nelson Delgado, that if he were ever trying to escape law enforcement authorities in the United States, he would try to get to Mexico and from there go to Russia via Cuba. "This is the way I would go about it."
From Oswald's rooming house, where he had stopped to pick up his gun, the nearest boarding point for use of the transfer was at Jefferson and Marsalis, and he had almost arrived there when he was stopped by Tippit.
The first southbound bus Oswald could have taken after the assassination left downtown Dallas at 3:15 p.m. and made a flag stop at Lisbon, which was part of the metropolitan area of Dallas. The Lisbon stop could be reached through the bus transfer, and the intersection of Jefferson and Marsalis streets was the only transfer point in the Oak Cliff section of Dallas where Oswald could have used his transfer. [emphasis added by me] Oswald had almost arrived at that transfer point when he was stopped by Tippit, no doubt because Oswald's description matched the description broadcast over the Dallas police radio after the assassination.”