UNIVERSAL CITY (CBSLA.com) —  If you think your commute is worse on some days, it’s not your imagination.

A new study reveals the days and times that have the most congested traffic.

According to researchers, the slowest night of all is Thursday.

Three companies – TomTom, Waze and INRIX – used GPS technology to analyze traffic patterns.

They found Thursday evening is one of the slowest. if not the slowest, drive-time of the week. Drivers spend 40 minutes of every hour sitting in traffic.

Why Thursday? Researchers say commuters leave work early because those with flexible schedules are taking Friday off or working from home.

Another explanation: there’s just a lot going on Thursday and Friday nights for locals and visitors.

So which freeway is the most delayed? The eastbound 10.

On average, commuters are delayed 50 minutes.

The study also found Los Angeles has five of the top ten most congested freeways in the country: the eastbound 10, northbound 405, southbound 5, eastbound 91 and the northbound 101.