Rear car light trails

Hello everyone!!
Im just wondering if any of you has some tips on catching cars trails with slow shutter. I have noticed that the rear car lights are difficult to catch in my photos. I understand that the front lights are brighter & thats why its more obvious in the photos, but i cant seem to get the back ones.. see the two examples here: https://www.facebook.com/photo.php?fbid=494553430583680&set=a.459740484064975.101943.451379921567698&type=1&theater&notif_t=like
& https://www.facebook.com/photo.php?fbid=464852596887097&set=a.459740484064975.101943.451379921567698&type=3&theater

Thanks in advance!
Cheers...

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Don't tell me sky is the limit when there are footsteps on the moon!!