Speed values do not work as expected inside CARLA

[Dactylif]

Issue

CARLA ignores speed values over 10 and speed values are interpreted as mp/h.
For example the value of 10 ends up at 16-17 km/h when checked inside CARLA, but a value of 20 also gets converted to ~16-17 km/h. Lower values affect the vehicle as expected, but are still interpreted as mp/h.
Neither do FollowLaneBehavior(EGO_SPEED) or do FollowLaneBehavior(20) from the example script work as expected.

Env

OS: Ubuntu 21.04
Carla: 0.9.12
Python 3.7
scenic: 2.1.0b1

Steps to reproduce

• Start CarlaUE4 instance
• Execute scenic example.scenic --simulate

Example script

The example script I used which is a slightly modified version from this one: https://carla.readthedocs.io/en/latest/tuto_G_scenic/

param map = localPath('../../../tests/formats/opendrive/maps/CARLA/Town01.xodr')
param carla_map = 'Town01'
model scenic.simulators.carla.model

## CONSTANTS
EGO_MODEL = "vehicle.lincoln.mkz_2017"
EGO_SPEED = 15
EGO_BRAKING_THRESHOLD = 12

LEADCAR_BRAKING_THRESHOLD = 10

BRAKE_ACTION = 1.0

## DEFINING BEHAVIORS
# EGO BEHAVIOR: Follow lane, and brake after passing a threshold distance to the leading car
behavior EgoBehavior():
    try:
        do FollowLaneBehavior(EGO_SPEED)

    interrupt when withinDistanceToAnyCars(self, EGO_BRAKING_THRESHOLD):
        take SetBrakeAction(BRAKE_ACTION)

# LEAD CAR BEHAVIOR: Follow lane, and brake after passing a threshold distance to obstacle
behavior LeadingCarBehavior():
    try: 
        do FollowLaneBehavior(20)

    interrupt when withinDistanceToAnyObjs(self, LEADCAR_BRAKING_THRESHOLD):
        take SetBrakeAction(BRAKE_ACTION)
        
## DEFINING SPATIAL RELATIONS
# make sure to put '*' to uniformly randomly select from all elements of the list, 'lanes'
lane = Uniform(*network.lanes)

obstacle = Trash on lane.centerline

leadCar = Car following roadDirection from obstacle for Range(-50, -30),
        with blueprint EGO_MODEL,
        with behavior LeadingCarBehavior()
        
        
ego = Car following roadDirection from leadCar for Range(-15, -10),
        with blueprint EGO_MODEL,
        with behavior EgoBehavior()
        
require (distance to intersection) > 80
terminate when ego.speed < 0.1 and (distance to obstacle) < 30