The main thrust of the river flow is known to hydrologists as the thalweg; it does not move in a straight and forward line but, mingling with the inner flow and the variegated flow of the surface and bottom waters, takes the form of a spiral or helix..
1 Some booster seats can be used for children up to 60 inches and 120 pounds. 2  Many state laws prefer that children 12 years and younger sit in the back seat if available. 3  Some states, as is the case in Michigan, forbid placing a child under the age of 4 years in a front seat if a rear seat is available. All children who are smaller than 150 cm (4 ft 11 in) and younger than 14 years old must use a booster or car seat appropriate to their weight. 2  A child must be either 14 years old or 4'11 to ride without a booster seat.
Even greater cause for concern is that a large child of 15 months who is in the 95th percentile for weight can easily approach 30 pounds. At that age a child's body is not developed enough nor likely to be tall enough for this type of seat. A good thing is that of the 28 booster seats with the lower allowable weight limits, at least half also include a minimum age limit of three and others include height limits that are more typical of a three-year-old.