  We report an experimental study of carrier density (n), displacement field
(D) and twist angle ({\theta}) dependence of temperature (T)-linear resistivity
in twisted double bilayer graphene (TDBG). For a large twist angle
({\theta}>1.5{\deg}) where correlated insulating states are absent, we observe
a T-linear resistivity (with the slope of the order ~10{\Omega}/K) over a wide
range of carrier density and its slope decreases with increasing of n, in
agreement with acoustic phonon scattering model semi-quantitatively. The slope
of T-linear resistivity is non-monotonically dependent on the displacement
field with a single peak structure. For device with {\theta}~1.23{\deg} at
which correlated states emerge, the slope of T-linear resistivity is found
maximum (~100{\Omega}/K) at the boundary of the halo structure where phase
transition occurs, with signatures of continuous phase transition, Planckian
dissipation, and the diverging effective mass; these observations are in line
with quantum critical behaviors, which might be due to the symmetry-breaking
instability at the critical points. Our results shed new light on correlated
physics in TDBG and other twisted moir\'e systems.
