The collision occurred in the village of Barna, Co Galway, at about 5.40am. There was no other vehicle involved.
The driver, in his mid 60s, died at the scene.
His body was taken to University College Hospital Galway for a post-mortem examination.
The road was closed for a time to allow a collision investigation by Garda forensic experts.
Investigating gardai at Salthill have appealed for witnesses.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? email@example.com