In addition to the tie down techniques mentioned above, here's what I add for a long trip. I use Ancra Integra straps with the soft tie option for the handle bars.
https://www.ancra.com/consumer/produ....php?prodid=17
A quality 36" bungee that goes from the top to the bottom of the hook areas. By that I mean the round metal portion that the strap is secured to. That way the bungee keeps the two attachment points in tension just in case you have enough spring compression to cause the strap to slaken and the securing hook to fall out of the attachment point on your truck or trailer.
I also add a second strap to each of the forward attachment points, but with just the slack taken out. Just in case all else fails.
Another option is to buy the swivel hook caribiner straps that replace the hooks and avoid the potetial mess described above. Here's an video ad - a picture is worth a thousand words.
I haul bikes almost every day - in a truck or on a trailer - and this works for me. Larry