merge: 'merge' produces 't-x' trajectories for a pair of lead and...
In PJOssenbruggen/Basic: Tools for Understanding Highway Performance

merge produces t-x trajectories for a pair of lead and following vehicles.

1	merge(df1,df2,leff,delt,ylim)

`df1`	leading vehicle, a matrix
`df2`	following vehicle, a matrix
`leff`	vehicle length, a number
`delt`	time-step size, a number
`ylim`	for plot, a vector

The merge, a wrapper function for bmfree2, xabparam and hsafe, returns a smooth hsafe rule t-x trajectory. for the following vehicle. The lead vehicle trajectory is not affected. Incidentally, inputs df1 and df2 were created with bmfree2 and used for testing.