There could be many causes, but IF your vehicle uses a mechanical speedometer cable then if the lubrication [grease] has dried out then the "sticking" of the rotating inner cable against the outer protective cable could be causing the tick.
The ticking noise is the metal cooling.
The fuel injectors make the ticking noise you hear at startup, especially when the engine is cold (colder temperatures).
there is a rattling noise in the area of the serpentine bell
If you are loading a Cd-rom,or a program.
well it sounds like your lifters are ticking The connecting rods screaming LET ME OUT!!!
horses make neighing sounds
you may have a bent valve
fasten your seatbelt
A Toyota RAV4 would make a loud noise while driving if a piece of hardware like the camshaft is damaged or something is caught in the drivetrain. This will result in noise and potentially costly repairs.
98 Chevy new 383 block 30k, ticking noise from sounds like heads . 210k on heads;
== == Could be a pebble stuck in the tread of one of your tires.The ticking noise only appears to disappear because the tone or pitch of the noise gets higher with speed to the point at which it is undetectable to the human ear.
Remove the muffler