From your sample, I suspect that the main point is the ability to set the property in markup. This is possible with the following approach, though it does not have too much in common with a Dependency Property in WPF.
In your UserControl class in the CodeBehind file (named UserControlName.ascx.vb), you can add a property Car that you can set in the markup. You can open this file in the context menu by choosing View Code
.
C#
public partial class CarControl : UserControl
{
// ...
public string Car { get; set; }
// ...
}
VB.NET
Public Partial Class CarControl
Inherits UserControl
' ...
Public Property Car As String
' ...
End Class
Markup
<My:CarControl ID="MyId" runat="server" Car="Ferrari" />