The state Bureau of Labor and Industries said an investigator found substantial evidence the driver stopped providing service because of the couple's sexual orientation.
Agency spokesman Charlie Burr said the next step is for an administrative prosecutor to decide whether to pursue formal civil rights charges. If so, an administrative law judge would hear both sides and make a ruling that goes to state Labor Commissioner Brad Avakian for a final order.
In the meantime, the parties will try to reach a settlement that could include anything from an apology to money.
In another case, the agency in January determined that the owners of a bakery east of Portland violated the rights of a same-sex couple by refusing to bake their wedding cake. In response to that controversy, a group plans to pursue a ballot initiative that would allow Oregon businesses to refuse service to gays involved in same-sex ceremonies.
Kate Neal and Shanako Devoll filed the complaint against the cab driver last September under the Oregon Equality Act, a 2007 law that protects the rights of gays, lesbians, bisexual and transgender Oregonians in employment, housing and public places.
The complaint says the driver, Ahmed Egal, disliked the couple's display of affection and made several anti-gay statements.
Neal tried to defuse the situation by asking Egal to stop the cab in a safe place and let them out. The driver, however, left them on the shoulder of Interstate 84, the complaint states.
The couple and their attorney, Nicholas Yanchar, declined comment Tuesday because the case remains active.
Egal called 911 during the contentious trip and reported that the women did not want to pay. He does not have a listed phone number and could not be reached for comment Tuesday.
He denied to investigators that he made anti-gay comments.
Egal was driving a Broadway Cab when he met the couple at Casa Diablo, a vegan strip club in northwest Portland. The vehicle was equipped with a video system, and investigator Jeremy Wolff examined the footage starting from when Neal and Devoll entered the cab about 11:40 p.m. on July 25.
The couple embraced and kissed for more than four minutes until 11:51 p.m., when their moods changed and Devoll appeared upset, Wolff wrote in his report. It wasn't long until they were out of the cab and on the freeway shoulder.
Labor bureau spokesman Charlie Burr said Egal was an independent contractor and the cab company is not a party in the complaint.
In August, the city of Portland permanently revoked Egal's taxi driver permit because he did not safely take the couple to their destination.