  New ALMA observations of protoplanetary disks allow us to probe planet
formation in other systems, giving us new constraints on planet formation
processes. Meanwhile, studies of our own Solar System rely on constraints
derived in a completely different way. However, it is still unclear what
features the Solar System's disk could have produced during its gas phase. By
running 2D isothermal hydro-simulations and a dust evolution model, we derive
synthetic images at 1.3 mm wavelength using the radiative transfer code
RADMC3D. We find that the embedded multiple giant planets strongly perturb the
radial gas velocities of the disk, creating traffic jams in the dust. They
produce over-densities different from the ones created by pressure traps and
located away from the planets' positions in the disk. By deriving the images at
1.3mm from these dust distributions, we show that the traffic jams, observable
with a high resolution, further blur the link between the number of gaps and
rings in disks and the number of embedded planets. We additionally show that a
system of 3 compact giant planets does not automatically produce bright outer
rings at large radii in the disk. This means that high resolution observations
of disks of various sizes are needed to distinguish between different giant
planet formation scenarios during the disk phase, where the giants form either
in the outer regions of the disks or in the inner regions. Finally, we find
that, even when the dust temperature is determined self-consistently, the dust
masses derived observationally might be off by up to a factor of ten compared
to the dust contained in our simulations due to the creation of optically thick
regions. Our study clearly shows that in addition to the constraints from
exoplanets and the Solar System, ALMA has the power to constrain different
stages of planet formation already during the first few million years.
