The ornamental design for a shoulderstrap for use in vehicles, as shown and described.
FIG. 1 is a perspective view of a shoulder strap for use in vehicles showing my new design;
FIG. 2 is a perspective view showing the present invention in an engaged condition of use;
FIG. 3 is a top plan view thereof;
FIG. 4 is a front elevational thereof; and,
FIG. 5 is a side elevational view thereof.
The indicia or broken lines shown on the figures are for environmental purposes only and are hereby disclaimed as forming no part of Applicant's claimed design.